Denying The Duke (Regency Romance: Strong Women Find True Love #3)
Virginia Vice

Duke Robert is a man of strong character and traditional views. But he finds himself taken with the young heiress -- and increasingly sharing her unpopular views. But she is a hard woman, and in an age where marriages are more about cementing family alliances and less about true love, it is not an easy match for him to make.
The two struggle to overcome their differences, and eventually find themselves thrust into unexpected danger, with the end result that Lady Amelia finally stops denying the duke.
This is a steamy 40,000-word Regency era romance novel with a HEA and female main character who is strong enough to think for herself.