Secrets of surrender / Madeline Hunter.

Enhanced descriptions from Syndetics:

First he'll learn her most intimate secrets. Then he'll arouse her deepest passions. He's the lover she's been waiting for: the man who can rescue her from her wicked past-for a price-in Madeline Hunter's tale of sin, seduction, and irresistible, impossible love.

He catches her eye across the dining room-a handsome stranger who stands out among the lewd noblemen and bawdy painted women. But their worlds are about to collide in a way Roselyn Longworth could never have imagined. For before the night is out, she will be auctioned off to the highest bidder...and Kyle Bradwell will lead her from one kind of hell to another. Yet from the moment he wins her, Kyle treats Rose with a gentleness she hasn't known since a family scandal destroyed her reputation. And when she finally learns what is really driving Kyle, it's too late. For Rose has fallen for the man who knows her most intimate secrets. Now he has stunned her with a proposal of marriage-the first step in a seduction that will demand nothing less than her complete surrender....