That's not Rinnosuke. Actually, I'm pretty certain it's Heida no Akyu myself. She does where a hakama-styled skirt, her sash is pretty apparent, and there are no glasses. Mamizou was done with her glasses on, so Rinnosuke would be, too. Also, if you look up towards Nazrin's side you can see the flower in her hair. Add to that who else is around her; the three fairies, Tokiko, and Ibara Kasen, and it's even more likely to be their fellow 'bookie' friend.
To top it all off, given the nature of Valentine's Day in Japan, is Rinnosuke really going to be in this image at all?
If someone wants to second me on this, we can remove the Rinnosuke tag and add Heida no Akyu.
There. Added a few notes, and a few characters who were missing. Also, I think I spotted some chocolate in this pic, so I added that tag too. Feel free to check for mistakes, though.