Just how much change has occurred because of the single act of letting Helga live. Not only were her memories wiped out, but it also brought up new memories for the people. Helga was hated by Lady Rohesia because she liked her son, and she feared that her son would fall for Helga. She was already talking about the king taking a hybrid as his wife and her son...
She had wanted to throw the lady out before even thinking about Evilyna. She had planned to kill her that night and act like it was an accident. Thankfully, none of them had confessed their feelings. That way, Leif would easily dismiss any lingering feelings and her death won't be painful for him.