Why is Xuan Nv's daughter called Rouge Ma?

Xuan Nv's daughter is called Rouge's mother: Rouge saved Xuan Nv and was Xuan Nv's benefactor. Rouge took Xuan Nv as her family, and Xuan Nv didn't want to recognize this daughter, so Rouge helped her raise her, so Xuan Nv's daughter was called Rouge's mother. This is the plot in the novel Sansheng III, which is very nice.