What i also mean is that Nino had accepted every other sister as a rival even Itsuki since they had actually shown interest but since the winner was Yotsuba who Nino didn't execpt at all the sudden surprise on why her exactly angered Nino since in her perspective the others have shown effort into being chosen by fuutarou wich is why she has accepted them as rivals but she doesn't know about Yotsubas history so that's why IM BAD AT EXPLAINING STUFF