Vietnam is relatively free of serious hassles for Western women. There are issues to consider, of course, but thousands of women travel alone through the country each year and love the experience. Most Vietnamese women enjoy relatively free, fulfilled lives and a career; the sexes mix freely and society does not expect women to behave in a subordinate manner.
Many provincial Vietnamese women dress modestly (partly to avoid the sun), typically not wearing sleeveless tops or short shorts and skirts. Big-city women tend to wear what they like.