Arima realized one more thing it is that he's mother love for him is a sorrow and when his mother said that he should be used of sorrow her mother did that because she was very sick and can't do anything for her son so the only thing he could do is make her son practice and practice so he could stay in the 1st place and also she wanted to see her son success on being a pianist because she didn't have that much time to live he realized that while he was playing piano in stage then the sound of piano suddenly change it's tone with all of how he feels and let everyone reach how he feels.
After the competition Arima received a letter from Tohka saying all how she feels about him and also she said goodbye cause she knows that she'll Die soon enough, Arima was shocked and go to the hospital immediately to check Tohka.