Tsuyoshi's adorable little sister. She is a fan of Sana. Aono carries around a store-bought egg in the hope that one day it will hatch into a chicken. One day, Sana buys a chick, and swaps it with Aono's egg when she isn't looking. Akito calls Sana an idiot for doing this because someday, Aono will realize what happened, and will feel stupid and humiliated. But Sana insists that as a child you should have dreams, and that the happiness it will bring Aono will be worth the small amount of grief later, because grief goes away, but happy memories are forever.
It is then that Sana realizes that Rei has been pretending to be her boyfriend the same way Sana gave Aono a chick – to let a child dream. This is how Sana finally gets over Rei, and starts to regard him as a friend and manager.
From: Wikipedia.org