I can personally vouch for his character.
4 seconds sound clip from the It's a Wonderful Life (1946) movie soundboard.
You can hear this line at 00:31:43 in the Blu-ray version of the movie.
Quote context
[...]
- I happen to know the bank turned down this loan.
- But he comes here, and we're building him a house worth 5000.
- Why? Well, I handled that, Mr. Potter.
- You have all the papers there. His salary, insurance.
- I can personally vouch for his character.
- You see, if you shoot pool with some employee here, you can come and borrow money.
- What does that get us? A discontented, lazy rabble instead of a thrifty working class.
[...]