Gaslight/Awesome

At the end of Gaslight, when Paula finally confronts her husband who turns out to be the man who killed her aunt years earlier, and had been staging incidents to convince Paula that she was insane, so he could get at the priceless jewels her aunt had left behind. After he has been apprehended by the police and tied to a chair, he tries to manipulate Paula into cutting his bonds and letting him free. Her response?

Paula Alquist Anton: It isn't here, you must have dreamed you put it there. Are you suggesting that this is a knife I hold in my hand? Have you gone mad, my husband? Yes, that's it.
[throws the knife away]
I am mad. I'm always losing things and hiding things and I can never find them, I don't know where I've put them. If I were not mad, I could have helped you. Whatever you had done, I could have pitied and protected you. But because I am mad, I hate you. Because I am mad, I have betrayed you. And because I'm mad, I'm rejoicing in my heart, without a shred of pity, without a shred of regret, watching you go with glory in my heart!

- The Academy agreed--Ingrid Bergman won an Oscar that year for the role.