Identify this honesty and integrity quote

Putting this in the Cafe Society because I think it’s a literary quote, but I may be wrong.

I heard someone say roughly the following on the radio recently: “Honesty and integrity are the most important things, and if you can fake that, you’ve got it made.” They were quoting someone, I believe.

Has anyone heard this quote before? I may be partially mis-quoting, but that’s the gist of it.

I’ve always heard it as “Sincerity is the most important thing in life, and once you learn to fake it, you’ve got it made,” but I have no idea who first said it.

I believe George Burns said “Acting is all about honesty. If you can fake that, you’ve got it made.”

I thought it might have been a Wilson Mizner quote, but a search shows it credited to Jean Giradoux, given as “The secret of success is sincerity. Once you can fake that you’ve got it made.”

That sounds right. Thanks!