But if after that she left, then I'd believe her to be as good as she is beautiful and I'd beg her forgiveness and marry her.

4 seconds sound clip from the The Picture of Dorian Gray movie soundboard.

You can hear this line at 00:32:25.563 in the Blu-ray version of the movie.

Quote context

[...]

- In that case, I needn't tell you how I should proceed if I were in your place.

- What would you do, Harry? I'm curious to know.

- Well, I should invite her to come to my house to see Basil's portrait.

- Then, when she said it was time for her to go home, I should ask her not to leave. She'd be shocked, of course. I'd pretend to be disappointed in her.

- If she still wished to go, I'd become cold and indifferent. I'd ask her to let herself out saying that I couldn't bear sad farewells or something equally appropriate.

- But if after that she left, then I'd believe her to be as good as she is beautiful and I'd beg her forgiveness and marry her.

- I've always thought your wickedness a pose. I know better now. You're an unmitigated cad.

- Will you try my experiment, Dorian?

- Miss Vane. Miss Vane, has Sir Tristan, as you have so charmingly called him ever invited you to see the wonderful portrait that Basil Hallward has made of him?

- No, he hasn't. I should love to see it. May I?

- Of course you may, darling. Tonight, if you wish.

[...]