Married to the Rake by Samantha Holt

Wallflowers and rakes do seldom mix well.
Miss Chloe Larkin is completely assured of that. Especially when said rake is a member of the Waverly family—the people responsible for a feud that has been ongoing since practically the dawn of time.
But he comes offering a deal…
The centuries-old feud between the Larkins and the Waverlys has taken its toll. Brook Waverly wants this fight solved. Now. His ageing father cannot take much more of the stress and he’s determined the problem shall be resolved before he comes to inherit.
So he needs her help…
Chloe is distrustful of Mr.Waverly—and rightly so. Not only is he her lifelong enemy but he has a reputation that would make the most experienced of women blush. And boy does he make this wallflower blush! However, she has little interest in continuing the silly feud and, with her little brother set to inherit one day and her father’s failing health, the sooner it is all over, the better.
Working with the handsome, and far too charming Mr.Waverly to get their fathers to come to an agreement is…interesting. Especially when he seems to be less concerned with ending the feud and more interested in her. Can she really trust him or is this just another way for his family to get their revenge on hers?