Scully: Mulder, you're the only one I trust.
—The X-Files, "E.B.E."
Alice is in a difficult situation: perhaps she's chased by the cops, or maybe she has a secret she cannot let out. She thinks she's completely alone against the world, but wait. Bob is there, and he's the only one Alice can rely on.
Discovering that there is only one trustworthy person remaining is a difficult moment. This is typically exploited to emphasize the sense of danger. That, and to build suspense around just whether that trust will be justified.
If the trust is justified, then it's probably directed to the Secret Keeper, The Consigliere, The Lancer (or The Dragon) or the Only Sane Man. When the person you thought you can trust betrays you, it slips into Et Tu, Brute?. See also The Power of Trust.
WARNING! There are unmarked Spoilers ahead. Beware.
- Nabari no Ou: Yoite and Miharu have no one else to turn to but each other after betraying Kairoushuu.
Yoite: I can only rely on Miharu-
- Same with Raikou and Gau, to the point that the two camp out in total isolation for two months after running away before accidentally being discovered by Raimei. If she hadn't found them, there's no telling how long they would have stayed there.
- "Help me, Obi-Wan. You're my only hope." Princess Leia's message to Obi-Wan Kenobi, sent via R2-D2 in Star Wars Episode IV: A New Hope.
- Ugarte: "You know, Rick, I have many a friend in Casablanca, but somehow, just because you despise me, you are the only one I trust."
- In Ultraviolet, Garth is the only person Violet can trust, as she's got nowhere else left to go.
- "You're my only hope" said by Roger Rabbit to Eddie Valiant in Who Framed Roger Rabbit?.
- In Shutter Island, Teddy Daniels calls and treats his partner, Chuck Aule as this, despite the two apparently meeting for the first time on the ferry to the island. Becomes even more poignant after you realize that "Chuck" is actually his longtime psychiatrist.
- In the Banlieue13 sequel, when Damien discovers he's been framed for drug dealing by the police department he works for, he promptly grabs a phone and calls Leito for help.
- Typical in the Pony Tale genre is that the heroine is The Only One The Horse Can Trust.
- Subverted in Artemis Fowl and the Opal Deception, when Artemis tells Holly that he'll only be able to break through the mind-wipe by hearing of fairies and the like from the one person he can trust. That person is himself. Luckily, he prepared a recording at the end of the previous book.
- In A Song of Ice and Fire, this is why Jon Arryn and Ned Stark were chosen to be Hands of the King Robert Baratheon, who was surrounded by a Deadly Decadent Court. However...
- Dumbledore in Harry Potter doesn't trust anybody with the whole truth except Harry - and even then, it takes an immensely tortuous You Are Not Ready rigmarole to get there.
- Turns out there IS one person he trusts as much as Harry in book 7: Severus Snape, as revealed after his death.
- In The X-Files, this is turned Up to Eleven. One of the taglines for the show is "Trustno1." Mulder and Scully make it clear often that they only trust each other and unfailingly.
- Played straight and subverted numerous times in 24:
- In an early episode of the fourth season, Jack and Audrey Raines are caught in a building surrounded by Marwan Habib's thugs, who have already murdered all the staff in the offices. Jack pulls out a phone and tells Audrey that he's calling "the only person I can trust" - nine minutes later, Jack and Audrey are saved from certain death when Tony Almeida arrives to rescue them from the building's parking garage.
- Jack references Chloe being his main (and only) tech support throughout the later seasons (especially when he's hiding out after he fakes his death in season 4), and later comments during the season finale that "I never thought you'd have my back all these years."
- Whenever Jack says, "You are our only [hope/evidence], I promise you can trust me," whoever he says this to dies shortly after (sometimes in the same episode).
- In the White Collar episode "Vital Signs", a drugged Neal tells Peter, "You're the only one I trust."
- When Inspector Lynley's wife Helen is critically injured in a car accident, Lynley asks his partner Barbara Havers to stand watch outside her hospital door - and though he takes his anger out on her when she has to, of all things, use the loo, he tells her later that he's terribly sorry, and that she is the only one he trusts to do the job properly.
- In Due South, Ray Kowalski spends an episode accused of murder. Worse, a concussion clouds his memory, leaving him doubting his own innocence. His partner Fraser refuses to doubt him. Meaning that when Ray can't even trust himself, there's always Fraser.
- Wheatley was always there for Chell in Portal 2. Until his Face Heel Turn.
- In Kingdom Hearts, Organization XIII member Lexaeus says this about Zexion, as detailed in his secret Journal entry in Days. The two, through their interactions, would seem to be Heterosexual Life Partners and Lexaeus seems to be loyal enough to Zexion that he could be considered Zexion's Dragon for Riku's portion of Chain of Memories.
- In Soul Calibur V, we see Pyrrha Alexandria say almost this exact phrase to someone after her recently rediscovered brother Patroklos threatened her with his sword and fled after she saves his life from Nightmare. Who does she trust in this time of emotional turmoil? Tira.
- Batman: The Brave And The Bold offers a subversion: in the episode with the Green Lanterns and Despero, the entire corps is missing and Despero has Mind Controlled Mogo the Living Planet into helping him take over the Earth. Batman is "helped" by three free Lanterns: Guy Gardner, who has a huge chip on his shoulder; G'nort, who is The Load and (almost) too dumb to remember the Green Lantern oath; and Sinestro, who is utterly dependable. So much so that Batman tells him outright... right before he decides that killing Mogo is the only way to make sure to stop Despero.
- Okay, she did mutate into something vaguely monstrous at the beginning of said fight, but it is the principle of the thing