Haruki hears about Kazusa's moving from her mother, who she hadn't been on good terms with.  He feels betrayed and angrily confronts her.  But his words force open the door to Kazusa's heart, which she had desperately tried to keep closed so that the three of them could stay together.
It's hard to believe I hated a
plain old mother like that for so long.
Es ist schwer zu glauben, dass ich eine 
gewöhnliche Mutter so lange gehasst habe.
Es difícil creer que odiara a una 
madre tan simple por tanto tiempo.
No me creo que haya odiado a una 
señora tan simple durante tanto tiempo.
Dire que j’ai toujours haï 
cette mère ordinaire.
Difícil acreditar que eu odiei