You can't make a leopard change its spots, or hitch a fire horse to a milk wagon. He'll be like a fish out of water.
7 seconds sound clip from the The Front Page (1974) movie soundboard.
You can hear this line at 00:20:58 in the Blu-ray version of the movie.
Quote context
[...]
- I wouldn't cover the last supper for you if they held it in the pump room of the Ambassador East.
- Now, you get the hell off the phone and let me speak to my girl.
- All right. All right. The flasher wants to talk to you.
- That was a rotten thing to do.
- It was for your own good, believe me.
- Marry an undertaker, marry a blackjack dealer, marry a pickpocket, but never marry a newspaperman.
- That's why I'm making him quit.
- We'll take our chances. Now, if you don't mind.
- Just a friendly warning. That's my wedding present to you.
- Darling, I'm sorry. I should've known better, but he just sounded so convincing.
- I finish my last show at 9:15. Will you pick me up?
- Tell him I wish him all the luck in the world and I mean it or my name isn't Otto Fishbein.
[...]