I know you for what you are. For a long time, I've had my suspicions about you and now I know I've been right.

5 seconds sound clip from the The Treasure of the Sierra Madre movie soundboard.

You can hear this line at 01:32:37.291 in the Blu-ray version of the movie.

Quote context

[...]

- Fred C. Dobbs don't say nothing he don't mean.

- As long as I'm here and can do anything about it, you won't touch a single grain of the old man's goods.

- I know exactly what you mean. You want to take it all for yourself and cut me out.

- No, Dobbs. I'm on the level with the old man, just as I'd be on the level with you if you weren't here.

- Get off your soapbox, will you? You only sound foolish out here in this wilderness.

- I know you for what you are. For a long time, I've had my suspicions about you and now I know I've been right.

- What suspicions are you talking about?

- Oh, you're not putting anything over on me. I see right through you.

- For a long time, you've had it in your mind to bump me off at the first good opportunity and bury me out here in the bush like a dog, so's you can take not only the old man's goods, but mine in the bargain.

- And when you get to Durango safely, you'll have a big laugh, won't you, thinking how dumb the old man and I were.

[...]