This Girl Is Mine — Mary Munro

Lee doesn't want to masquerade as the bride-to-be, but her friend leaves her no choice. After all, it was Sally who guided Lee's modeling career when she first arrived in the city, young, inexperienced, and fleeing an impossible love and the unhappy memories of her past life.

Bored with constancy even before the wedding, Sally convinces Lee to her stand-in at a luxury resort until Sally's fiancé is due to arrive. But tough, arrogant Mark Hunter shows up ahead of time and uncovers the deception. In his bitter anger, he forces Lee to take Sally's place far more intimately than planned! Their relationship -- born of misunderstanding, distrust, and resentment -- should be doomed from the start.