I Want to Eat Your Pancreas (Kimi no suizô o tabetai , Japan)

A high school boy stumbles across a secret journal in a hospital one day. He soon finds out the diary belongs to his classmate, a girl named Sakura Yamauchi, who is revealed to be suffering from a terminal illness in her pancreas and only has a few months left to live. A secret they share that brings their hearts closer together.