She saw what love made people do.
They become jealous. And didn't we call the one being loved "object of their affection"? Object, while the other who go near are jealoused. Because love mean being possessive of who you love.
Kokoro wondered why. She was so loved. Everyone thought she was so lucky because she was a reverse harem heroine after all. She have all the male leads attention, she have all their love.
All their envy. Their jealousy. Their possessivity.
It was decided for her that she was blessed by the rule of the universe she lived in as the heroine. Other women hated that. Even in that universe, other girls hated her for that.
Kokoro didn't know as she was just a character. Chiemi the transmigrator couldn't tell her the truth about the world she lived.
So Chiemi decided to be there for her.
Why?
Because she had enough of doing nothing. She had enough of both of her doing nothing.
And maybe Kokoro wasn't strong enough to do something about her role.
But Chiemi the transmigrator didn't have one. So it was time for her to chose, she decided.
She will protect Kokoro.
And she will never fall in love.
If it's what love make people do.