Sims Medieval help please?

I'm on a quest with my wizard. she's trying to prepare the 'enslave' spell, but everytime i do it she makes the 'mend tormented soul' spell because they both have the same runes in the exact same order!! i've tried forgetting the spell and trying again and also trying to prepare the spell while already having the tormented soul one memorized, but it just tells me that she has prepared a spell she already knew!! i can't move on with my quest until i know this spell. someone please tell me what to do?!?