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.
I can't help it if I'm not good yet.
Tut mir ja leid, 
dass ich noch nicht gut bin.
No puedo evitarlo si no soy bueno.
No puedo hacer nada si soy tan malo.
C’est normal que je sois 
un peu maladroit, non ?
Fazer o que se ainda sou ruim?