It's in His Kiss

Charlotte Lightwood has one season to find a husband or she'll be forced to marry her guardian's loathsome cousin. With no title or dowry, she doesn't have much hope of making a good match. Sebastian Wilkinson, the Earl of Marley, has been the most eligible bachelor on the marriage mart for more years than he cares to count and is very aware of his duty to marry a woman who will add to the wealth and stature of his title. Sebastian makes Charlotte an offer she can't refuse: he will pretend to court her to help her attract more suitors in exchange for her advice about which ladies he should pursue. As they work together, their mutual attraction grows. When they realize they just might be perfect for one another, they must decide whether to bow to the dictates of society or follow their hearts.

Each book in the It's in His Kiss series is a standalone, full-length story that can be enjoyed out of order.
Series Order:
Book #1 Just a Kiss
Book #2 One Last Kiss