Cousin Mark (Harlequin Romance, 1534)

Could she marry just to save her home? Damaris loved her home, Ravenscrag, more than anything else in the world. Under the terms of her grandfather's will, the only way she could keep it was to marry his heir -- her unknown cousin Mark. Young and inexperienced, Damaris thought she could carry out the plan -- especially if Mark was elderly and kind. That was why, when she met Christian Trevor, she told herself very firmly that she must be careful not to fall in love! (goodreads.com)