Love Letter (1986)

"Love will come soon if enter zip code."

Tawat, a young millionaire secretly in love with Namtip, disguises himself as a mail-man and delivers his own love letter to her every day. One day he got bitten by her dog, so she invites him to have dinner in her house just to compensate for what her dog has done to him. After that, they always chat every time they see each other.