The duke and the lady in red
(Book)

"When Rosalind Sharpe gains the attention of the deliciously wicked Duke of Avendale, she's torn between her distracting attraction to the notorious rogue and the knowledge that he, rich as Croesus is the perfect target for a deception that will put her swindling days behind her. However, Avendale is no fool. After he discovers the tantalizing lady packing up to leave London with his coins in tow, he confronts her with a scandalous proposition: she can have all the money she requires ... for a week in his bed. Desperate for the funds, Rose agrees, but on one condition: he must never question her motives. Avendale quickly sees beneath her mask and discovers she is more than passion and pleasure she is everything he has ever desired. But claiming her requires he unveil her secrets and lose her forever. Unless he can put his own dark past aside and risk everything for a chance at love." --,(Source of summary not specified)