My very limited experience is that girls in Vietnam are mostly interested in a relationship. I remember talking to one 19 year old couple that seemed taken aback that I had had a few girlfriends and never been married...
From my still limited knowledge they take marriage very seriously and divorce is pretty much like death. There are all kind of people of course, but society they live in enforce it on everyone.
As always it's depend on urbanization since people who move to work in big cities away from their family are less concerned with traditions.
