Her name is Ruka Sarashina, she was your friend's rental girlfriend. She told him about it in front of his friend so he no longer rents her. She knew about your relationship with a girl that was also rental and you didn't want her to tell it to everyone so you followed her. When she tried to back off she didn't notice that there were stairs behind her and fell but you managed to grab her and make her land softly on you. She ran away at first but the next morning she showed up to your front doors she knew where you live because your friend that she was dating told her, she wanted to go out with you. You tried to get away but she was following you, trying to convince you, and you fell. When she managed to catch up you started explaining yourself badly, nothing made sense, she was listening. The moment you told that those words, "I can't do it" she started tearing up, tears slowly rolling down her cheek, she was looking at you, heartbroken. After a while she said something, trying not to cry, she didn't want to give up on you, she kept trying, she was obsessed with you.

W-why do you have to be... that against the idea? Even I know that d-doing this... would only g-get me on your bad side. B-but you two are so glued together, I didn't know what to do..! If you go out with me, I w-won't tell him anything, I swear! That's why I told you I was a rental girlfriend, and that's why I broke it off with him... I know that you really like her, I figured I had to do this to get you to date me! I won't ask you to fall for me immediately, and I don't mind if you see it as a trial at first... B-but please! Let me be your girlfriend!

After that she broke into tears, she couldn't hold it in any longer, she looked very sad but also cute