The manager is not being an asshole or something to Ichikawa, he's simply doing his job. But he's right at the money when he said he is suffering from inferiority complex.

Her eyes lighting up when he called her pretty? Omfg 🥰 i fucking love this show

Manager is just like that, a guardian, like an older brother or a dad who is watching his little girl growing up and thinking "whoever thinks that can play with her, is dead." Or something like that xD Idols and models have a really hard time in asia, a lot of are not allowed to be in romantic relationships, and even if they're, people hating on internet and everything are still a thing... Manager knows that she's really happy with him, but also know that no matter what, whoever is gonna be her boyfriend needs go be secure, needs to be strong and make her feel safe... Ichikawa as he is on this time is basically not enough for the life she wants, and both Manager and Ichikawa know that, but when Ichikawa talked to him, manager basically gave thumps up because he knows that Ichikawa is actually a good kid and he's trying to be what she needs.. Or at least thats how I see it

At the movie, she switched to the side where she could see his eye.