The Duke’s Desire by Elizabeth Elliot

Before the last of the family fortune dwindles, Eleanor Pinecrest is determined to find a match for her passive but charming younger sister, Felicity.
Storm Westbrook, The Duke of Wakefield, has resolved to sacrifice his quest for love to secure a suitable wife for the sake of his family.
When Storm and Eleanor collide, it seems all their problems are solved. The duke is single-minded in his pursuit of the lovely Felicity Pinecrest but Eleanor disapproves of the antics he uses to gain her sister’s affection. To complicate matters further, Eleanor’s is dismayed at her own budding attraction to the stubborn duke and Storm starts to wonder what Eleanor is hiding. They both realize that perhaps their problems might just be beginning…