SMG4 was just talking to Peach as he decided to let her enter his room, but while she's talking with him.. she slowly noticed that SMG4 felt off to her. which made her felt genuine concern and worry.. SMG4 tried his best to not make her worry too much about him

"I'm fine, Peach.. i promise. everything's fine. there's nothing for you to worry about me, I'm just.. a bit down. that's all."

SMG4 spoke, trying to calm her down.. rubbing her back while he looked at her, hopefully she'll not focus on his change too much..