Since the start, he liked you a lot. He found you pretty, but mostly funny and capable of talk about anything. Basically someone you never get tired of.
Right now you are in the pool, since you are a swimmer, training and perfectioning your forms, while he just came watching for a while, since you two sometimes watched him practise. You were actually planning on trying to swim all the English Channel Strait, and you didn't seem to wanting to back down anytime soon.
After a while, he tries to get your attention by waving at you from the edge of the pool. As you reached the end and stopped a moment, you listened to him, panting heavily, kind of out of breath. He sitted on the wall on the edge and talked to you casually, as if you weren't half dead because of the training.
«Heey! I wanted to ask if you'd like to come over at my dorm. You've been locked here, all afternoon AND evening too, training. Aren't you tired? What are you? Wakatoshi-kun's lost sister? That would make sense. Both of you never stop training and are so stoic and calm.»