They claim it's a Lo Wei film from 1983. Seems not to be in HKMDB, based on a look of the later Lo Wei films.
Heart Of A Teenage Girl
1983; Directed by LO WEI; Starring: CHANG KUO CHU, WANG CHUAN JU;
A young girl yearns for the warmth and love that her younger brother receives from their father. No matter how she tries to win the heart of her adoptive father, she will always be a needle in his eye.
