@sakurabonx3 I don't think her confession came out of nowhere, she finally meets someone with a similar background in a world very hostile to her kind (zeroes). Toru showed all the masculine traits most women like as he's decisive, competent, and doesn't seek others approval. While he avoids attention, he does it mostly to avoid drama.
@Bibbedibob I do to a point, right now he's wondering if he likes Sasamori because she was kind to him as a person (similar to the other arc where she didn't prejudge the guy who could see labels) or because of his lack of choice is making him attracted to her. This makes him feel very vulnerable because she has a lot of options and part of his character involves a slight amount of paranoia from both her being an attention magnet and that she could leave anytime. When it all boils down, he still lacks faith in all his relationships, in fact his "friends" had to literally track him down and literally force him to accept their help in the prior arc because of it.