Watching that scene again when they are talking about her being a witch, and he asks her ''why help?'' and she says ''I dont want anyone else to get hurt and I dont know how to stay out of it''

Did you see the way he was staring at her?, it seemed like a realization hit him, like he just noticed how they are similar in the way they think. They both got involved, cause it was kinda thrown on them, and they both are still involved because of wanting to protect people.