I don't love you yet
Goodbye, My Dearest Best Friend
S1 E14:
Ren moved to Shanghai. Being away from each other, Yo and Ren both became workaholics. Ryusei was not satisfied for Yo neglecting him and their relationship didn't go well. Yo suddenly wanted to talk to Ren, but no courage to talk directly, she only talked to the voice message. At that time, Ren was still writing his feelings on a postcard, with no plan sending it out.