A Mongolian Tale 1995 one on netflix

Bayinbulag and Somiya are brought up, from a young age, as brother and sister by their adoptive grandmother. The three live happily in a yurt on the Mongolian steppes. Just before Bayinbulag is to leave for the city, to be trained as a vet, the grandmother suggests that Bayinbulag and Somiya should eventually marry. Bayinbulag, now training to be a musician, stays away for long periods of time without communicating with Somiya. He finally comes back expecting to marry her.