You should not tolerate being abused by your family.
Amy's sisters, Jane and Carol, are jealous of Amy's boyfriend and good looks, so they constantly verbally assault her.
Amy wants to decide how to handle her sisters.
Amy starts insulting Jane and Carol right back and asks them how they like it.
Amy just ignores the things Jane and Carol say in hopes that one day they will just stop.
Jane and Carol get Amy's point and begin to change their behavior.
Jane and Carol see Amy as weak because she doesn't respond, so their attacks get worse.