[WWTBC] human and ghost romance

I had read this book a long time ago and wanted to reread it but couldn't find it on my kindle anymore and I couldn't remember the title either...

It starts with our FMC who is an author buys this house by the beach as a holiday/relaxation home to regroup and get back in her writing flow. While residing in the house she meets the MMC who is a ghost who had been murdered in the house and is haunting it. The plot progresses and they fall in love, FMC delivers the letters written by the MMC before he died to his now dying son to get closure. However when the FMC returns the ghost has left or has passed on. Then later the grandson of the MMC comes to greet our FMC and calls her by the unique nickname only known to the two protagonists, hinting at possible reincarnation.

I really want to read it again...