The Sleeping Demon — Anne Herries

Even though she had known from the beginning that he had eyes only for her cousin. Jane had given her heart of Captain Stuart Smithson. When she learned that he had drowned at sea she tried to hide her grief, but the memory of him haunted her dreams, and she knew that she would never love again. When the stern missionary Obadiah Thorne and his sister Sarah came into her life, she decided to sacrifice herself for the girl's sake. After all, she had nothing to hope for for herself. Fate, however, had a few surprises in store....