It is Kyoko mostly because she doesn't want to get hurt. So she put up a box in her heart with multiple locks that no one can open, but Ren always manges to open all. And what does Kyoko do she puts more and more impossible to open lock on the box. I am over here like can't you just what ever happen happens between you and Ren.
I get the feeling that Ren is also being super protective of himself as well, though. He hurt someone important to him and he's afraid of repeating that mistake as well as the fact that he doesn't know how to deal with his emotions. So with both characters like this, they are unlocking each other's boxes, but development is incredibly slow.
Kyoko needs to get rid of those locks and let Ten enter because he will never hurt her. And Ten he need to figure out that he needs Kyoko because she is the only one who can keep him in check over his feelings in the past of when he accidentally killed him best friend
that's true. but normally there'd be some kind of big triggering event because shoujo manga. and then just the fact that it's pretty hard to open up because they've already experienced trauma so they'll feel too vunerable
I hope they will get together, because so far they have feelings for each other but scare to move forward.