Some type of romance book (historical?) set in the west, a lady goes seeking her brother I think with a guide falls in love and at some point saves an Indian lady

[Tamara]

So pretty vague, it’s been years so hope I’m not combining stories, but the book that I’m looking for the heroine races to the rescue of an Indian, I think they take her home and care for her, and when she’s better she runs away with one of their horses, but I think she was a chiefs daughter or something and at some point in the story I think the tribe bring back the horse, and maybe come to their rescue at some point?