Happiness (ハピネス) is a japanese novel by Novala Takemoto, which also got adapted into a manga by Taki Sei.
Synopsis[]
A cute story written by a master of pure love novels!
"We are in the second year of high school and started dating because of a story about her socks. One day, when I had a medicore day, she suddenly told me "I'll die next week". Knowing the progression of her illness and accepting her destiny, she wants to live in her own way for the short time she has left. I couldn't keep up with her and struggled to fulfill her wishes. It's a little cold so I want to warm you up. The next time I wake up, she will be gone."
The transparent last scene will hit you right in the feelings. It is a sad and pure love story that orthodoxly inherits the genealogy of the masterpiece "Missin'" that is also known as the Otome bible.