- No, I believe you put the toughness on to save your skin.
- Oh, you think so?
- I know a little about that.
- Do you?
- Quite a lot.

17 seconds sound clip from the The Philadelphia Story movie soundboard.

You can hear this line at 00:38:30 in the Blu-ray version of the movie.

Quote context

[...]

- Couldn't you afford to buy my book?

- The bookstore didn't have one.

- Well, are you sure you're doing the right thing? You know what happens to girls like you when they read books like mine. They begin to think. That's bad.

- These stories are beautiful. Why, they're almost poetry.

- Well, don't kid yourself. They are.

- I can't make you out at all now.

- Really? I thought I was easy.

- So did I. But you're not.

- You... You talk so big and tough, and then you write like this.

- Which is which?

- Both, I guess.

- No, I believe you put the toughness on to save your skin.

- Oh, you think so?

- I know a little about that.

- Do you?

- Quite a lot.

(woman shushing)

- Look, let's get out of here.

- This book, it was just such a complete surprise to me.

- Look, let's walk, shall we? It'll be much more fun.

[...]