Historical highland romance

Hi, I’m going crazy trying to find this book, I only remember a few details though. The heroine was being sent off to marry the laird of a rival clan I believe, her brothers and father were awful to her accept for one brother. She had a sister, and both her and her sister were said to be lovely, but in different ways. Her sister had an innocent angelic sort of beauty and she had a more sultry seductive sort of beauty. That became a big point in the book somehow. I know it was set in pre-culloden Scotland. If I had to guess Medieval times but I’m not sure. Anyway, if this pops out at you please let me know any details you know, or the title/author. Thank you so much!

Do remember anything else to narrow it down? A specific scene or name? The look of a scene, anything? It’s hard to recognize covers because they change them but the details within stay the same.