Faithful Heart — Janet Cookson

Tamzin and Laura Thornham's father had converted their country house in Devon into a hotel some years before. After the business falters, he sells it to Canadian entrepreneur Rob Hunter, extracting a promise that his daughters would always have the right to reside there. When Rob appears to be forming a close friendship with her beautiful younger sister, Tamzin hides her own feelings, aware she might be losing the man with whom she's fallen in love...