Trai mồng một, gái hôm rằm
Direct English translation
A boy on the first day of the month, a girl on the full-moon day.
Giải thích tiếng Việt
English explanation
A folk saying based on superstition, claiming that boys born on the first lunar day are unruly while girls born on the full-moon day are flirtatious. It is used to refer to the belief that a person's birth date can predict their character, though it has no scientific basis.