- Hold on. What if he tests the stuff out?
- He won't.
- Well, how do you know that?
- Because I know he won't. I'm positive.

10 seconds sound clip from the Boogie Nights (1997) movie soundboard.

You can hear this line at 02:06:35.890 in the Blu-ray version of the movie.

Quote context

[...]

- So we're gonna do the deal. We're gonna drop half a key of baking soda into a bag.

- We're gonna walk over there. We're gonna... Boom. Right there.

- This could be a nifty bit of hustle-bustle.

- Wait. Do you have his address?

- Fucking, Reed, yeah. I got his fucking address.

- What? Yeah, okay, question. Sorry.

- Hold on. What if he tests the stuff out?

- He won't.

- Well, how do you know that?

- Because I know he won't. I'm positive.

- You guys should be careful.

- Scotty.

- What?

- What do you mean, what? Do me a favor. Just mind your business, please. What the fuck?

- Sorry.

- Anyway, heh...

- Dump it in there good. Dump it in clean.

[...]