Isabella just like Norman, discovered the truth behind plantation, fallen in love with Leslie, but instead trying to escape gave up and became a monster.
Isabella got inseminated during her indoctrination, since Ray doesn't have childhood amnesia, he heard her song while still in her womb.
Isabella knew about him being her son, still decided to ship him out to be eaten though, so her wishful thinking now isn't giving her a glimpse of redemption in my opinion.