That's very good of you.
4 seconds sound clip from the Beat the Devil (1953) movie soundboard.
You can hear this line at 00:21:44 in the Blu-ray version of the movie.
Quote context
[...]
- Tea for two and two for tea.
- Now, that's most awfully kind of you. You shouldn't have troubled, really.
- Billy tells me you have a chill. A bit of one. On the liver. Too tiresome.
- There.
- I feel just now I should like, somehow, to do him a good turn of some kind.
- You do?
- Well, naturally. Oh, I see. Naturally.
[...]