
That's easy. She tried to seduce Mahiro into sleeping with her that time when she fully thought that he has a girlfriend. It doesn't matter if it was a misunderstanding that was cleared up later on because AT THAT TIME SHE FULLY THOUGHT THAT HE WAS ALREADY IN A RELATIONSHIP AND STILL TRIED TO SLEEP WITH HIM! SMH.
Ooh wow, I liked it. It was short, dark, and twisted. Completely psycho, my cup of tea. I think that psychological tag is in order for this one.