Is This Correct Italian?

“Buona sera, la mia bella Donna.”
I’m trying to say “Hello, my beautiful lady.”
It’s for a book I’m writing.
It’s a man saying it to a woman (obviously). The situation is supposed to be fairly formal (like trying to flatter a business partner), so that’s why I used “Buona sera” (that, and it’s going to be said in the afternoon).