Kakeru enters the soccer club as a provisional member, just as the letter says. When the topic of lunches comes up after practice, Kakeru jokingly asks Naho to make lunch for him as well. Naho finds herself bewildered by his words, but feels pushed to act by the letter from herself 10 years in the future, which tells Naho that she wishes she had made lunch for Kakeru.
I wish I'd never read that letter.
.أتمنّى أنّي لم أقرأ تلك الرّسالة أبدًا
Hätte ich doch nur nicht
diesen Brief gelesen.
Ojalá no la hubiera leído.
Ojalá no la hubiera leído.
J’aurais préféré 
ne jamais l’avoir lue.
Avrei preferito non averla mai letta.
Eu não deveria ter lido aquela carta.
Хотела бы я никогда его не читать.