Some people are just naturally talented at persuasion and manipulation, the type of people who would make great lawyers if they have the intellect. She doesn't necessarily have to be a witch, but I believe all such abilities connect with naturally with magick on a certain level. Magick is, after all, when we focus our will and believe something will occur, manifesting it. People talented with charming others (in a pleasing not magick sense) just have a more hands on approach. We don't need to cast a spell to exude a certain energy and impress our will.
I would agree that a spell to bind or freeze may work, but I would alternatively suggest that you cast a ritual to reveal the truth to those you desire not to be fooled. Be sure before casting such a ritual that your truth is the real truth and not a bias viewpoint, or else it could backfire on you. Truth spells are tricky like that.