A romance manga about a girl going deaf in her right ear
It should be "Kieta Hanbun, Nokotta Real" (Half Gone, Love Remains) oneshot from "Kiss to Koukai" by Mio Nanao.


  A broken school festival sign and a common love for music makes best
  buds out of Naru and Yamato. That is until Naru loses all hearing in
  her right ear and she keeps her condition from Yamato a secret...