[Kaoru Chujo]

You can say "immature," but you can also say "innocent and natural." Almost everyone else is hiding things and not expressing themselves, but she accepts her own feelings and lets them out, when she recognizes them.

There is something about her character design that makes me think she may be ill. Maybe it's the eyes, and/or the messy hair. Or the fact she seems young for her age, both mentally and physically. Might Jun be setting her up with Shin because he knows she has a limited time left to experience these things? Just a (horrible) thought.

I was just rewatching early episodes (highly recommended) and noticed again the scene where Shin is thinking about Hiromi's tears and hoping an angel will show up to take them away. Then he has a vision of Noe, seen from above her in the tree -- before he has ever met her in real life. This shows a fated connection between them, but whether it is as a romantic partner or just as the angel that wipes away Hiromi's tears, I'm not sure.