In all my years reading manga, I've never seen such a ruthless combo of flaming roasts.
1) Ichinose says her looks are only about average
2) He calls her out on her lack of integrity/character, as evident by the fact that she immediately turned to another man (her ex's bro no less) for comfort after being rejected by her ex
3) He shatters the delusion she was laboring under that cute girls such as herself can get away with anyway, which in this case can only mean that she wasn't cute enough to get away with anything at all.
This is the kind of aggressive, no-nonsense attitude authors seldom have the balls to give to their protagonists. The rest of the manga might be whatever, but this one part is rather extraordinary.