Hesitation Equals Dishonesty

The lovechild of Law of Conservation of Detail and Realistic Diction Is Unrealistic, Hesitation Equals Dishonesty is ubiquitous to the point of being unnoticeable. Whether engaging in Blatant Lies or making sure to Let Them Die Happy, any time a character visibly hesitates when relaying information (rather than, say, making an emotional appeal) to another character, it's even money or better that they're being dishonest, and are trying to barely avoid Saying Too Much.

Since Viewers are Morons, they probably won't know that the hero's family was in fact NOT... Released to Elsewhere and that the "reward" the traitor... deserved... is in fact death without the simple and ever so subtle clue of a significant hesitation.

The trope extends to videogames, even to the dialogue of the player characters: Even if Statistically Speaking the PC is an excellent liar, there's a good chance the writers will mark his Blatant Lies with the all too subtle "Why, yes.... I AM the assassin you've ordered".

Sadly, belief in this in Real Life makes things even more difficult for those of us who aren't perfect communicators. Fridge Logic should indicate that the guy with the perfectly-rehearsed story is probably lying his ass off (or is extremely well-spoken, but there's a noticeable difference between the two), rather than the guy who occasionally pauses to collect his thoughts. Subtrope of You Can Always Tell a Liar. Compare Seamless Spontaneous Lie. See also Last-Second Word Swap and If You Know What I Mean.

Anime and Manga

 * This is used in the unaired episode of Kodomo no Jikan. When Reiji asks Rin what she and her friends were doing (making a birthday gift for Aoki), she hesitates a few times when trying to claim they were doing schoolwork. He actually notices it, but either believes her when she says she isn't lying or decides to let it go.
 * During the Mahora Festival Story Arc of Mahou Sensei Negima, Haruna flatly asked Yue if she got jealous when the former kissed Negi. When Yue tried to deny that accusation, Haruna noted that she took a fraction of a second too long to answer and that the old Yue would have smacked her for being an idiot immediately. Busted.
 * In Sound Stage X of Magical Girl Lyrical Nanoha, Teana asks if she, and after a surprised pause, she says no. Teana does some more investigation into this as a result of noticing  reaction, and eventually , pointing out that the way she responded was what tipped her off.
 * Mostly inverted in Bakemonogatari. A good rule of thumb in this series is the more straightforward someone seems to be, the bigger the lie they're concealing. Nadeko is hesitant and lacks self-confidence, and her "big secret" is that she likes Araragi (secret only to Araragi, really); on the other hand, Suruga is quite forthright with her sexuality but no so much As it turns out, her provocative teasing of Araragi is probably

Comics

 * Relentlessly used in Silver Age comics, but only when the reader knows it's a lie. A lie that is part of the twist ending (and thus not known as a lie to the reader) will be delivered blithely, while if we know the character is lying, every sentence will begin with "Um...".
 * In the first issue of The Tick (animation), a man on the street asks Tick if he's the guy who just broke out of the insane asylum (He is). Tick ums and ers for about half a page before coming up with the answer "No."

Fanfiction
"Draco paused for a moment, weighing, and then opened his mouth - "I see he did," said Harry, and Draco cursed himself, he should've known better, only it had been hard to decide. Later Draco had listened carefully, but he hadn't detected any hesitation or tremor."
 * In Harry Potter and The Methods of Rationality, Harry spots that Draco was considering lying with this, and Draco believes that Harry is telling the truth because he doesn't stammer.

"Kyon: Well, I have to head back in anyway, since ... I forgot my shoes. Yeah. I'll see you tomorrow, alright, Tsuruya-sempai?"
 * Kyon does this in Kyon: Big Damn Hero when Tsuruya asked why he had to return to the clubroom despite he telling her before he was dismissed for the day. It turns out he had to find Mikuru to Time Travel back to the next day.

Film

 * In the ending scene of Back to The Future, Marty asks Doc if he and Jennifer become "assholes" in the future and the Doc says they both turn out fine. The sequel establishes the Retcon that Doc was lying to protect Marty from the Awful Truth. In Part II, the refilmed version of that scene (refilmed to accommodate the Jennifer swap) has Doc hesitate before answering Marty's question.
 * Doc hesitates, gives a squinty look out the corner of his eye, and stammers just a little on answering. In the original in Part I, the scene is shown from the rear of Doc; we don't see his face or his expression.
 * This is actually reversed in Stranger Than Fiction. After a disastrous first meeting, Harold encounters Anna Pascal on the bus, and stumbles his way through an apology, outright stating that he 'ogled' her and it was wrong. She accepts his apology... "But only because [he] stammered."
 * That's... why I'm here!
 * Averted in Inside Man. When Jodie Foster confronts Christopher Plummer, asking him if it was true that he used to work for the Nazis in WWII, he hesitates for about four seconds...then smiles and says "Yes."
 * Either he was a truly honest man, who was old and had nothing to lose, or he realized that hesitating that long before lying about it would make it obvious that he was lying.

Literature

 * In Murder on the Orient Express, when Poirot mentions to Hector MacQueen the letter naming Daisy Armstrong, the secretary interrupts his own reply. Poirot deduces that MacQueen is involved with the cover-up.
 * Both played straight and averted in ((Discworld)). While pauses do often hint at lies, several characters, especially Sam Vimes, note that instant responses are even less honest.

Live Action TV
"KITT: Where are we? Everything is so dark... is it night? Bonnie: ...Yeah."
 * Jon Lovitz's "The Liar" character from Saturday Night Live. "Yeah... that's the ticket!"
 * From Get Smart: Max's "Would you believe?" segments often included this.
 * Smallville's Clark Kent is the king of this, pausing for years before delivering a horrible explanation for something that has even the slightest correlation to his being an alien. If you're going to pause that long, Clark, at least come up with a plausible explanation, will ya?
 * This is likely done deliberately to characterize the upright and honest Kent as a particularly terrible liar, at least using TV-language.
 * In Heroes, when Matt tells Daphne he believes she's reformed, the poor guy is told Hesitation Equals Dishonesty, with the extra twist that the amount of time he hesitated was only significant to someone with Super Speed.
 * Averted on Lie to Me: characters point out that prepared lies generally cause people to answer more quickly because they have already prepared their story for questioning. The way to catch these people is to ask them to repeat their story backwards: your average liar won't bother to practice enough to get this right, but someone telling the truth will obviously be able to draw on their memory to answer. It's also mentioned, however, that hesitating is a way to make people think you're lying.
 * In one episode of Monk, Monk's assistant asks him if he saw some embarrassing pictures of her. He hesitates for about a minute (no exaggeration intended), refusing to meet her eyes, before he responds "no". Then, as he walks away, he wretchedly adds, "Yes."
 * Pick a crime drama, any crime drama... Sometimes seems you can't go two episodes without this trope being the only reason a cop or prosecutor declares someone to be lying, no matter how logical or reasonable what the suspect says is.
 * Lost's Benjamin Linus falls into the trope rather absurdly. 98% of what he says is at best a half-truth, and after several seasons it's still hard to tell which was which. But whenever he says something the audience already knows is a lie (like, say, that ), he hesitates.
 * Played with on the Panel Game Would I Lie to You, where hesitating can be the sign of a bad liar ... or a Genre Savvy panelist trying to appear to be lying.
 * Knight Rider pulled this now and again (since at least one character can only communicate with a words, and a series of little red lights, his hesitations were usually blindingly obvious.
 * Then there's a scene in one of the traditional smash-KITT-up-so-we-can-redesign-him-for-the-new-season episodes:

"CHANDLER: Okay, well. Janice said 'Hi, do I look fat today?' And I, I looked at her... ROSS: Whoa, whoa, whoa. You looked at her. You never look. You just answer, it's just a reflex. Do I look fat? Nooo! Is she prettier than I am? Noo! Does size matter? RACHEL: Nooo! ROSS: And it works both ways."
 * Explained on Friends "The One With the Jam" where Chandler is explaining his problems with Janice which includes him pausing before what could be considered a white lie.

"Dean: Did Balthazar really unravel the sweater over a chick flick? Castiel:....Yes. (not meeting Dean's eyes) Absolutely. That's what he did."
 * Invoked on Frontline, when Brooke edits a pause into the interview of a priest accused of rape to make it look like he's thinking about his answer.
 * In a season two episode of How I Met Your Mother, Ted is trying to catch Robin out in a lie by asking a string of questions about the wedding she claims that she had. When she hesitates answering a question about the catering, he immediately takes that as his in to accuse her of lying, but she quickly covers by saying that she wasn't sure how to answer the question as there were multiple possible answers. She's got rapid-fire responses for all his other follow-up questions about the ceremony until he gets to "Husband's name?" to which she just stammers in response. It turns out that she is lying and was never married.
 * Supernatural - after Balthazar rewrites history by un-sinking the Titanic, and is then forced to reset things by a very angry Fate, Castiel and the Winchesters have this exchange. The boys think Balthazar did it because he's a chaotic headcase who hated the Titanic movie, but Castiel knows it was

Newspaper Comics

 * Mark Trail plays this ludicrously straight. Begin your sentence with "um" and you're the villain.

Video Games

 * Fallout, and doubtless many other older RPGs without (much) spoken dialog, use this trope to quickly convey to the player that a particular dialog tree choice is... the gospel truth, of course.
 * Fallout 3 takes a ...different... approach, marking the PC's Blatant Lies with the subtle tag  at the end. Surprisingly few of these  are Speech skill checks, many are simply accepted at face value by the NPCs, often to heartbreaking effect.
 * Planescape: Torment does the same thing, and in some cases you get dialogue choices that say the same thing, but have different tags.
 * e.g. if you want to force someone to tell you some information, you can tell them that you will kill them if they don't answer. Choosing the dialogue option "Lie" means that you're bluffing, while "Truth" means that you actually intend to carry out the threat. Usually, the only difference between two options like this is the effect on your Character Alignment.
 * Girl Stinky of Sam and Max does this constantly.
 * The Porre ambassador in the Chrono Trigger Fan Sequel Crimson Echoes inserts significant hesitations into EVERY SINGLE ONE of his lines. Him not being on the up and up therefore comes as a tremendous surprise to the player.
 * Iji when lying about.
 * In the 1st Degree definitely plays this straight. When you question the defendent Tobin and pin him about the phone message of him threatening Zack, he says "I was trying to...persuade Zack to withdraw the claim." He's lying, you know it and the prosecutor you're playing as knows it.
 * Eggman's public announcements in Sonic Colors are often full of these, at least whenever he's not being brutally honest.

Western Animation

 * Parodied/subverted in The Simpsons: Bart's announcement of, "Well, I'm doing a presentation on...fireworks!" is met with his mother saying, "Bart, I wish you wouldn't lie like that" before confiscating said fireworks. Cut to Springfield Elementary, where Skinner is announcing a fireworks show, courtesy of Bart.
 * Also subverted when Marge asks Homer where he's going, and he replies 'I'm just going outside... to stalk... Lenny and Carl', which is exactly what he was planning to do.
 * Played straight (And very noticably so) when Homer asks Marge whether she thinks he's smart or not. She hesitates for quite a while before answering 'yes'. He then asks why she waited so long to reply. After a second long pause she answers 'No reason'.

Real Life

 * Richard Dawkins was asked in an interview if he could "give an example of a genetic mutation or evolutionary process which can be seen to increase the information in the genome" -- a question that, he later said, "would only be phrased that way by somebody who doubts that evolution happened." He famously paused for eleven seconds before answering, and the tape was used by creationists to claim that evolutionists don't have all the answers. Dawkins explains he had actually just realized that the documentary being filmed wasn't what he thought it would be, and was trying to decide whether to throw them out or not. His full, non-"soundbite" answer can be read here.
 * This Cosmo article is doing its best to make the belief more prevalent. Note that it counts both significant hesitation and simply SWALLOWING while having a conversation.
 * Ruthlessly mocked by Cracked here
 * Military recruiters. Hesitate for any reason, and they automatically assume you're a liar. Especially the Marines, who accuse you of "lying to the government" and legally threaten you.