More tragic love story than thriller

My Cousin Rachel - Daphne Du Maurier

Considered by some to be Daphne Du Maurier's most feminist novel, "My Cousin Rachel" follows the story of wealthy orphan Philip Ashley, and his two cousins - Ambrose and Rachel.
Due to health, Ambrose spends his winters in warmer climates, leaving his cousin (young adult, Philip) in charge of his vast estate. While in Italy Ambrose falls in love with and marries Rachel, but letters sent home suggest that Rachel may be trying to poison Ambrose. Philip heads to Florence only to discover Ambrose is dead and Rachel has gone.
Rachel arrives in the Cornish estate soon after Philip's return. She appears to be a lovely woman, cultured, intelligent and unlike the few women Philip has encountered. She overcomes his anger at Ambrose's death with her intriguing gentleness and Philip finds himself falling in love with her.
The tension comes from not knowing whether Rachel is manipulating Philip or Philip is misinterpreting her words and actions. In many ways it's a tragic love story, while in other ways it's a story about a woman trying to negotiate her way in a world determined to misunderstand and control her. I enjoyed it very much.