She doesn't believe me. Show her your driver's licence or Diner's Club card or something.

8 seconds sound clip from the Breakfast at Tiffany's movie soundboard.

You can hear this line at 01:14:51 in the Blu-ray version of the movie.

Quote context

[...]

- 'Varjak, Paul. Nine Lives.' And then a lot of numbers.

- Do you think they really have the book itself, live?

- Sure. Follow me.

- Number 57. That's us.

- Fifty-seven, please. Nine Lives by Varjak, Paul.

- Did you ever read it? It's absolutely marvellous.

- No, I'm afraid I haven't.

- Well, you should. He wrote it. He's Varjak, Paul, in person.

- She doesn't believe me. Show her your driver's licence or Diner's Club card or something.

- Honest, he really is the author. Cross my heart and kiss my elbow.

- Would you kindly lower your voice, miss?

- Why don't you autograph it to them? Don't you think it'd be nice? Sort of make it more personal?

- Really, miss...

[...]