The Letter(2004)

Original title: เดอะ เลตเตอร์ จดหมายรัก

Dew, a young computer programmer, takes refuge in Chiang Mai. There, she is reunited with Ton, whom she met during her aunt's funeral, and discovers that he is the love of her life. Sadly, Ton is plagued by a brain tumor and passes away prematurely.