Orange (2015)

During the spring of her 16th year, Takamiya Naho receives a letter from her future self. Upon reading the initial page of the letter, her class was introduced to a transfer student from Tokyo named Naruse Kakeru. The letter, she realized, was an account of the things her future self had experienced and regretted the most. Frightened, she tries to avoid reading further, but as her interest towards Kakeru blooms, Naho eventually decides to encourage him. Naho, together with the help of her friends Suwa, Chino, Hagita, and Azusa, do their best to avoid having the same regrets their future self had and heals Kakeru from his desolation and self-blame.