Number 6, and you're very welcome to it.
5 seconds sound clip from the The Oklahoma Kid (1939) movie soundboard.
You can hear this line at 00:12:28 in the DVD version of the movie.
Quote context
[...]
- I'd be glad to let you have my room, ma'am.
- Well, that's very kind of you.
- Thank you, but we couldn't put you out.
- Just a minute. What room do you think you have?
- Number 6, and you're very welcome to it.
- That's all right. They'd be glad to do a favor for a lady.
- That's awfully generous of you, but I really don't know how to thank you.
- Not another word. Just leave it to me.
[...]