The Maltese Falcon
written by John Huston, from the novel by Dashiell Hammett

(He looks away from her through the entire monologue)
Spade: When a man's partner's killed, he's supposed to do something about it. It doesn't make any difference what you thought of him, he was your partner, and you're supposed to do something about it. And it happens we're in the detective business. Well, when one of your organization gets killed, it's - it's bad business to let the killer get away with it. Bad all around. Bad for every detective everywhere.
Brigid: You don't expect me to think that these things you're saying are sufficient reasons for sending me to the--.
Spade (interrupting): Wait'll I'm through. Then you can talk. I've no earthly reason to think I can trust you, and, if I do this and get away with it, you'll have something on me that you can use whenever you want to. Since I've got something on you, I couldn't be sure that you wouldn't put a hole in me some day. All those are on one side. Maybe some of them are unimportant - I won't argue about that - but look at the number of them. And what have we got on the other side? All we've got is that maybe you love me and maybe I love you.
Brigid: You know whether you love me or not.
Spade: Maybe I do. Well, I'll have some rotten nights after I've sent you over, but that will pass. If all I've said doesn't mean anything to you, then forget it and we'll make it just this: I won't because all of me wants to, regardless of consequences, and because you counted on that with me the same as you counted on that with all the others.

Kudos and much thanks go to for this monologue , it is very much appreciated.