What happened towards the last couple of episodes: there was a girl going to a house with two kids and a lady, I think it was the orphanage she was raised at.
She said she had sisters so it could be her twin sister, because when she was going into the house as the train was going by when the main characters stole the girl from the hospital, the train was going by.
She said "I smell Kurumi" which was the sick girl he broke out of the hospital so after they did what they did and then had sex later on down the line, the main character girl ends up dying and the girl with the mole in the long hair and the big boobs I didn't know nothing about the OB club her twin sister went to visit in.
They could have worked it out for her dying wish to marry the guy that she loves so he will always be happy and you know and she dies without him knowing then they end up getting married. That's why she has the ring on her finger and she doesn't remember anything about before the golden shower and other stuff, because remember she did say she lives in an orphanage with her kids brothers and sisters, he could have had a twin sister.