BetoJR, I'll try to clear all the confusion that scene caused for you. First of all, neither of them think that they are in a relationship. Alto is taking care of Sheryl, staying by her side as he promised earlier. He does all of this out of his kindness and compassion. I believe he hasn't even thought about this situation as a form of a relationship. I don't think he dares to think about it this way. He is fulfilling his promise and that's that.
As for Sheryl, she enjoys the situation as much as she can. Still, she understands that all of this, the dinner and the time together is mearly taking advantage of his kindness. She also states that this kindness is a sin. It makes you indulge in it without any consequences. I believe Sheryl, as strong as she is, doesn't want it to stay like this. This makes it for her all the more painful. She also believes that Alto doesn't really care for her in a romantic way. The scene at the rooftop and the way she overhears Alto's conversation with Klan confirms it. She only hears the last part of the scene, without the proper context.
As I stated in my other post, I don't believe Alto is ready to give Sheryl what she needs. On the other hand he only needs a small poke in the right direction.
I think those will help a little
Post 1
Post 2
Post 3