@feha
Because I think the one who did it is Anna. Nearly every reincarnate generally has some kind of cheat ability, even if its just knowledge from our world that lets them manipulate and alter their new one.
Since Anna seems to have been rather worthless (saw nothing that made it seem like she had anything more than common knowledge or capabilities), she was probably given strong 'magic'.
She makes the most sense, since she needs to remove her current problem. Acting like you believe, and then stabbing someone in the back is pretty normal. Especially since I'm beginning to think that Anna is going to become the villainess.