This is what they called schadenfreude, no? She didn't want him and now she wants him (maybe? After realizing the effort he put?) as soon as he finds another girl that can keep up with him?
It's amusing really, but I got a bad feeling that things might take a turn for the worse, as in things might get very ugly
I don't think that's what is going on here... She said herself, it's not what she was trying to say. She is just really dumb and doesn't know how to word it. The other girl is right, she doesn't actually love Ota, she loves the ideal that Aga created. In reality, she probably does like Aga....but she's so blinded she doesn't even realize it. Tho judging by that flashback, someone is clearly laying in a hospital bed, probably the MC...which makes me think that Himawari made this world in the first place, and that's why she isn't with Aga.
My theory is, Aga in the original universe confessed, she said no, and he tried to kill himself and got into a Coma, so in a depressed spiral she made an alternate universe where he's alive but she subconsciously feels so guilty she keeps saying no to him. Either that or she said yes and he got into a coma from protecting her.