- How do you think I know?
- Of course, of course.

5 seconds sound clip from the Five Deadly Venoms movie soundboard.

You can hear this line at 01:10:31 in the Blu-ray version of the movie.

Quote context

[...]

- You should thank me, know why? When I'm through in here, they won't behead you.

- Hang him up and announce tomorrow that he committed suicide.

- Go on.

- Fixed it, huh?

- Of course.

- Listen, how do you know?

- How do you think I know?

- Of course, of course.

- You're all friends, oh no, we're all friends.

- Yes of course, we're all friends.

- People have told me you have ways of killing without leaving a mark. Well so have I. Like this needle here, which pierces the brain.

- Men Fua waits for you.

- We tore up his throat by using a very long hook, ripping. And tell me, did you ever use that one?

[...]