"If you behave, I will find you a husband," some minor nobody in the middle of nowhere would suffice. There were a hundred of those. Or for Ember go with her husband's insistence of marrying her to one of their bannermen. It would keep her well out of the way of accidentally making a mess of things.
She didn't think Ember had enough of a brain to make a mess of her plans on purpose.
"I won't lie to you, daughter, things at court are going to be different now. Dangerous," not like they hadn't been before, "And if you toe one step out of line you will be putting us all at risk. A transgression worthy of a scenic life in the middle of nowhere, don't you agree?"