As for the opinions, you can't always please everyone. It might be a good idea to let her step down too so she can just ignore defending that kingdom and have fun with her family instead.
Looking at that villain's frustrated expression earlier, I doubt he can come up with anything too convincing. Perhaps he will try to use the angle of wanting Nell to be more securely under the kingdom's supervision. That is, she must marry a person of importance in the kingdom. But such suggestions are easy to shoot down. After all, the kingdom needs Nell. Nell doesn't need the kingdom. That's the fundamental truth.