Well, Peter, I can tell you're a good boy. You'll get your fire engine.

5 seconds sound clip from the Miracle on 34th Street (1947) movie soundboard.

You can hear this line at 00:16:42 in the Blu-ray version of the movie.

Quote context

[...]

- Thanks.

- No. Thank you, Alfred.

- This way, please. Right this way, please.

- Yes, yes, yes. Peter's a fine name. What do you want for Christmas, Peter?

- I want a fire engine just like the big ones, only smaller. It has a real hose that squirts real, wet water. I won't do it in the house. I'll only do it in the backyard. I promise.

- Psst. Psst. Macy's ain't got any. Nobody's got any.

- Well, Peter, I can tell you're a good boy. You'll get your fire engine.

- Oh, thank you very much.

- You see? I told ya he'd get me one.

- Mmm. That's fine. That's just dandy.

- Listen, you wait over there. Mama wants to thank Santa Claus too.

[...]