- I've got to tell him.
- Tell him what, darling?
- I've got to tell him.
- Well, if you've got to tell him, you've got to tell him, I suppose.

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

You can hear this line at 01:37:15 in the Blu-ray version of the movie.

Quote context

[...]

- To me? Oh, I doubt that. I doubt it very much, dear.

- You don't know. You don't know.

- Well, maybe I shouldn't, huh?

- But you must. You've got to. I couldn't stand it if you didn't.

- What am I going to do?

- But why to me, darling? Why ask me? Why do I come into it anymore?

- Aren't you confusing me with someone else? A fellow named Kittredge or something?

- George!

- George. Splendid chap, George. Very high morals. Very broad shoulders.

- I've got to tell him.

- Tell him what, darling?

- I've got to tell him.

- Well, if you've got to tell him, you've got to tell him, I suppose.

- But if he's got any brains at all, he'll have realized by now what a fool he made of himself.

- How? Hello, George? This is... Yeah. Look, George, I don't care whether it's bad luck or not, but I've got to see you for a minute before the wedding.

- What? No, I didn't get it. Right. Right. Come on the run. He sent a note over at ten o'clock.

- Good. I told you he'd come to his senses.

[...]