rinne生日快乐

So, I just listened to the drama cd of Island. Since my japanese isn't the best and I lack of context ( I have only watched the anime) I have some questions. The drama cd deals with Rinne getting married it is meant to be an epilogue for the ps vita version but was added to the ps4 version later on (so most likely to the steam version as well. Here are the things I didn't get: Why does Rinne say that she is not the real one? Why does she think that she doesn't deserve it to...

主要就讨论一下大家都多长时间肝完的ps：当初走莎罗线没看过攻略无bd直通hd

do you have to get to the 2nd part of the game before finding any? i got the game elsewhere and i've played pretty far in and haven't seen in adult content yet so just wondering if this game has any

the visual novel is much better