Note 01
Literally, Junichi uses the term "ANZEN", which has many meanings. In this case, it means "Nothing's wrong; I'll be fine like this", but it can generally mean "I'm calm", "I'm a good person", or "I'm a nice guy". A few scenes later, Kotori reflects on the fact that she hasn't managed to charm Junichi; in the tub, she refers to him using the term "ANZEN SUGIMASU", which is to say "He's too MUCH of a nice guy". She's just annoyed because Junichi is too loyal to his feelings for Nemu to give her a second look.