The scene at the end of this chapter is big feels. It strikes home for me personally, having known bullying and how cowardly most bystanders are. All the instances of people going 'not my problem' when an issue is right in front of them add up to a trail of damage across lives, and hypocrisy when the former bystanders someday are themselves lost without help that could have been easily given. Humans suck.
Rei, offering what may be the rest of your life to someone isn't a small thing... It's touching how he doesn't consider any implications, just that his friend proves there are people good enough to have not let him suffer and thus she's a very special existence to him. The scene was also beautifully done in the anime version.
Geez, this manga and A Silent Voice really deliver some gut punches by dwelling on lonely characters.
Yeah, I really enjoyed this scene, and a later, related scene quite a lot in the anime. To me, this is basically Rei more-or-less proposing to Hinata long before he actually proposes (or even confesses or asks her out... that's honestly a big reason why I'm here, too- to continue past the anime's endpoint and see their relationship properly take form), let alone realizes he feels that way about her, yet, and that this promise will just experience evolutions and amendments until it reaches that ultimate conclusion.
Anyway, these two have been relying on each other for pretty much the entire story. I feel like the first proper moment they had hinting towards the eventual inevitability of it was her walking off after Obon, thinking about her mother. The parallels of her walking quickly away there, and her literally sprinting off here... And in both instances, Rei was right with her to keep her company in her dark moments...
Edit: Seriously, though... how do people not see the implications of this as something beyond just friendship? The other major events between them are more or less the same- their feelings for each other growing as Rei runs to comfort her and take care of her. And then, finally, in Chapter 71, you have Hina being bright after just about everything's resolved and literally dancing while leading Rei by the hand! (handholding?! That's lewd!!!)
Before this point, they had less dramatic moments, but even subtle moments together mean something for their growing fondness for each other.