Mirei didnt either from what i remember, but she was pretty gentle and protective of Mamori, Mirei was the sweetest TTvTT Of the two, Mirei is the real cutie. I don't remember when it seems like Mirei had feels and all, she always seemed attached in a way, a fondness that seemed to escalate. I'll probs rewatch it sooner or later.
I took it for granted while I was watching the series based on the attention and affection she showed Mamori, and how annoyed she was with Mamori's thing for Akira. I thought the most damning evidence was during the flashback to Mirei's past. She gets arrested for protecting a girl who looks just like Mamori, and it's established that she's no longer connected to any organization by the start of the first episode, so she latches onto Mamori, by my estimation, because she's her type.