I'm also shocked. Out of all those people, it's Yuna! One of the smartest things for the girls to do and she pulled it off! Well, not that it would be too hard to come up with that strategy in RL, but we are talking this romcom's standards here. Clever girl.
I especally like how this time around she isn't trying to slut her way in, but simply is honestly trying to spend time and creating memories with him. AND without all that BS about fairness among love rivals, which ultimately leads to others butting in, when stuff gets interesting, which is always frustrating for us readers.
AND she took one of MC's first times! The first time he brings/invites/awaits a girl home! And she did make that important first imnpression on the parents. Suck on that rest of the cast!
I really can't hate all of that. Honestly Yuna wasn't even among my Top5 for MC till now with all that cheap slutting around she did. I guess she did, what she knew might work, and now came up with something different, something closer to adults dating called "getting to know somebody better". This shows real interest and real initiative. Determination! I do like that soooo much!
(Itachi also isn't among that Top5, but that's because she is for me.)