"I know you." (I knew you, is the reality, and even then it was for such a short period of time.) "You showed me what being a magical girl was really about. We're supposed to save everyone, but I couldn't even do something that simple."

Especially at home, where she's sure she would have stopped being useful before long. She doesn't know what's waiting for her, back there, but even if she's determined to change things now (hah), she can't undo how much of a failure she was in the past.

"I won't just give up and become selfish, but..." She sighs again, and rubs at her eyes; trying to ignore the weight of the past week. "That's not enough. I've made too many mistakes to be friends with someone like you."