I believe you are thinking of Ruth. Ruth was not a descendant of Moab. She was called a Moabitess [Ruth 1:4] because she lived in Moab. Ruth was an Israelite of either the tribe of Gad, Rueben or Mannessah [Number 32:1] and therefore a suitable ancestor (Israelite) of Our Lord [Deuteronomy 23:3].
Thanx & yes, I was talking about Ruth. Throws out one of the “foreign” women in the author’s theory. I love getting dragged back out of the wilderness, cuz my quick searches sure aren’t getting the job done.