I think the FL's mom was related to the other family
That makes sense since their eye color is similar
Fl mother and the duke wife are sisters
Spoiler:
I’m pretty sure that the wanna be saint and the true saint are sisters. That the dad had an affair and the mother Saintess mother and she was born. So the goddess didn’t lose faith in that family the dukes adopted daughter was just born first. But I’m not sure if her bio-father is aware of her birth.
Ravienne was born 1rst if im not wrong 1 year early. Her dad thought when he liked Esthet mom it was ok cause he had already a daughter. But when Esther's mom ( little sis of Esther's bros) told him she was pregnant he sent killers....Catherine ( Esther's mom) died a few days after giving birth....
Okay three possibilities are going through my head right now:
1. Either the girl with the blonde hair & red eyes isn’t from the family, like someone’s mama had a fling with another man didn’t know who the baby daddy is or someone was adopted into the family.
2. The FL is a long lost semi-close relative from the family the saint made a promise to.
3. That family has always done this cruel method is pretending to be the saint, and have gotten away with it till now.