Found: 1980's romance novel title?

I am looking for the title and author of a 1980's romance title and can't find it anywhere. The book was about a British heiress whose mother sends her to masquerade as a prostitute in a high end brothel in Italy? to teach her about men. She meets a man named Alex who buys her at a flower auction but she escapes before he finds out she is an imposter. Years later he meets her again when their family businesses plan to merge. They have a weekend tryst, she gets pregnant, and he takes her to New York? as his wife until the baby is born. I can't find this book anywhere.

I think this Evening Star (also entitled Sweet Surrender) from Catherine Coulter
When Alex Saxton wins virgin Giana Van Cleve in the infamous Roman Flower Auction, he never expects to lose his heart...

>2 lesmel: Yes! Thank you!