Amnesia of Love

Yuu just got back from his long heroic trip with helping the special ability teenagers from dying... the only problem is Yuu forgot his memories because all of those powers that he had to set inside of him, Nao gave him a study translator note that he kept for a long time, the only problem is that he forgot what it meant. He was rescued and sent back to japan and Nao was there waiting for him, he forgot who she was and she said she was going to be his lover, Nao finally regains his memories with the time passing and Yuu finally decided that he wanted to marry Nao, but then problems occur with distrust and dishonesty with another guy, and what will happen during that time?