Here you are, Tommy.
3 seconds sound clip from the Miracle on 34th Street (1947) movie soundboard.
You can hear this line at 01:19:35 in the Blu-ray version of the movie.
Quote context
[...]
- If Your Honor please, I can.
- Will Thomas Mara please take the stand?
- Who, me?
- Tommy, you know the difference between telling the truth and telling a lie, don't you?
- Gosh, everybody knows you shouldn't tell a lie, especially in court.
- Do you believe in Santa Claus, Tommy?
- Sure, I do. He gave me a brand-new Flexible Flyer sled last year. And this year...
- And, uh, what does he look like?
[...]