Many fans consider her confession to Shiratori on national TVthe crowning moment of awesome for Hijiri.
If her confession wasn't that, standing her ground against a gang of catty freshmendefinitely was.
Chapter 47.1 has one for Nanami. Nanami hears Reina and Sumika arguing, and shows up in time to see Reina get pissed off enough to hit Sumika — in past meetings, Reina would restrain herself from beating up Sumika whenever the latter insulted her because Sumika can't fight. The sight of Sumika's bruised face causes Nanami to go ballistic, and she punches Reina in the face so hard that it knocks the latter off of her feet, something that Nanami was never able to do before. Even though it turns out Reina and Sumika staged the argument at Manabu's request in order to snap Nanami out of a Heroic BSOD, it doesn't take away from Nanami's accomplishment, because she wasn't in on the plan.
Reina channels her inner Bright Noa via punching Manabu after telling her about his tragic backstory and the choice he has to make, chastises him for not telling him stuff like this to his own girlfriend and calls him out for using her as an emotional crutch to ride out his wave of misfortune. But it doesn't end there; she tells him that she's gonna help him because she wants him to be truly happy. Manabu couldn't have picked a better person.
Reina's next course of action? She goes with a bat to Manabu's family home to demand a talk with his mother. When that fails and she is expelled from the place, she comes back, this time bringing his grandpa as a hostage and actually hitting him as proof that she isn't going to leave until she has that chat. And it works!