^^Aside from many previous instances of Ochaco showing deep concern for Toga, in the lastest chapters (393, 394), Toga is going berserk, her frustration with the world's unfairness overflowing, Ochaco tries to get through to Toga, gets stabbed and is bleeding out, but eventually she's got Toga to open up to her.
The exchange is currently going like this:
Ochaco (already stabbed): "That smile of yours is so perfect, I'm jealous (...) I don't want to pretend I never saw your amazing smile. I can't erase all your crimes (...) but if any part of you still feels like talking to me, you can have a lifetime's worth of my blood, so let's have that chat about romance!"
Ochaco, internally: "My body is going cold, but what matters right now is that I want to reach out and touch that sorrow inside of you
[Some more struggling as Ochaco tries to get close but not hurt Toga. Ochaco gets slashed some more, but eventually gets close enough, Toga comes back to her sense. They embrace with Ochaco's legs around Toga's hip, Toga tells Ochaco the root of her painful frustration with the world, mostly how she falls in love very easily with every one she met, but the world has been ingraining in her that she's creepy and gross, and it festered on from there. Then they deliver these lines in tears:]
O: "(...) May be I'm no replacement for the League, but I want you to know how special I think you smile is"
T: "Do... you really... think I'm cute?"
O: "The cutest girl in the whole world."
So yeah, can't help but shipping them harder and harder.