multiple personality, might be :-?
Oh, that'd be a possibility as well.
I'd actually prefer if she was pretending to be a nice girl to fit in with societal expectations of being a woman, and she's actually frustrated at people who solely appreciate kindness, warmth and softness in a female and who believe fake interactions are essential to blending into a specifically designed structure in order to achieve happiness in their lives.
multiple personalities, amnesia, etc are such unnecessarily dramatic and overused anime/manga plotlines
The thing is, if the former was true, she'd come across as an extremely petty and unlikable character to most people, like one of the radical feminists people make memes about. Since appreciating kindness and warmth in people is completely normal and should not be changed.
I could see a variant of the former where she seems like a nice person but is actually really cruel or something being true, but in yuri stories that's definitely more cliche than amnesia and multiple personalities.
Amnesia question mark?