Partial memory loss. All she'll remember is the broom and the threat. Since the "Marisa" part didn't harm her and wasn't fully remembered, she feels a subtle relaxation and sense of security around her. This can easily be mistaken for love.
Clearly, Marisa planned it all from the beginning.
Bang!ABwa-ha-ha-ha!
I'm a cursed broom!!I will eat a bad child in one bi--te?!Ha-ha-ha-ha