Funny how all these characters are constantly deluding themselves.
Saori pretends she's not interested in taking care of Shizuku, but she can't leave her alone and actually gets some pride out of being Shizuku's only "friend". Because she's been taken care of by her sister, she feels the need to take care of someone.
Shizuku pretends to be a loner, an outcast, a hardened delinquent, but she's actually kind at heart and weak to people who seem to care about her. She pretends relationships don't work for her, but she values them immensely.
I can see what Mikanuji is trying to do with all these couples, but she takes it really slow...