Plumed Bonnet / Mary Balogh 241 p. 5 Gold rings challenge

Alistair Munro, Duke of Bridgwater is bored when picks up a colorfully dressed woman walking alone along the road.  Her story is so predictable he knows it as she tells of being an impoverished governess who has just come into money and property and needs to make a good match pronto.  Her stories so entertain him that he carries her to her destination where he realizes that her story is true.  He does the honorable thing and offers marriage.  She accepts believing he is kindly gentleman.  Then her life is turned upside down where his mother teaches her to be his duchess--a total personality change for her.  She does everything properly, to be worthy of him.  He didn't want her to change but he failed to tell her.  Bridgwater knows of love that has thrived in arranged marriages.  He has hopes for his.  When he feels he must tell her his real reason for picking her up, she is taken aback, deeply hurt, and the marriage takes a new turn in this slow-paced, sensuous historical romance.