Ah. Plaid.
I was a Ririsu person and I kinda still am, but since the mid of the story I can't deny Ebino. It is pretty obvious which girl should win. Ririsu had her moments with Tarou and those weren't few nor low yield impacts, but she let those feelings willingly starve off. And there is a (rather good) reason for that. -> Eve. She would just go all blingbling and get purified(=death in there mindsets). Yet still she did let those feelings go to waste.
Well, those are Ririsu's circumstances and Ebino profits from them, but Ebino doesn't know about it. And even if she would have gotten a clue, what if!?! Huuuh? (*agressive*)HUUUHHHH?!?? It doesn't matter. THAT if! She pursued her love and has a real chance to get through to tsundere boy. She wins fair and plai...square.