Makoto is surprised by Saki's confession of love and has to clarify that he is not the girl Saki thinks he is. However, Saki is undeterred and throws herself wholeheartedly into the mission of becoming Makoto's first love. 
You can't know that.
Woher willst du das wissen?
Eso no lo sabes.
Eso no lo sabes.
T’en sais rien, ça.
E che ne sai?
Não tem como você saber!
Мы этого не знаем!