Vietnam is the most controlled society in Southeast Asia, and sexual, or even just personal relationships are not encouraged by those in control, from the national government down to the local police.
The people themselves, including young women, have a more friendly mindset, but the controls pretty much put a lid on what otherwise could come out of this.
Among the many measures prescribed by the government in order to keep Western men and local girls apart from each other are regulations that forbid Western men and local girls sharing a hotel room. This even applies to prostitutes, which is why men who do hire prostitutes have to rent two hotel rooms at a time.
Even though, rendezvous’ between Western men and Vietnamese prostitutes are regularly disturbed by the police busting into the hotel room occupied by the two.
These raids are not so much motivated by a genuine concern for communist morals but rather a method to part foreigners faster of their money than could be the case through state-promoted tourism programs, or to get more out of them than would otherwise be possible.
Such efforts match state policies. Many foreign investors have left Vietnam after trying their best for a few years, mostly because they felt cheated by officialdom. The impression is widespread that many regulations in the economy primarily exist in order to levy charges on foreign investors... regulations and charges of which those said (and sad) foreign investors had previously not been aware of.
In spite of the above-mentioned discouragements, it is worthwhile to try to have a temporary sexual relationship with a young Vietnamese woman (and I am not talking prostitutes here).
The point is that of all East Asian people (Chinese, Korean, Japanese, Mongolian, Tibetan, Thai, Laotian, Khmer, and Vietnamese), the Vietnamese probably have the most beautiful women. Many are of slender elegant built, with fine facial features... in two words: real beauties.
However, your best bet to mingle with Vietnamese women is in Cambodia, not in Vietnam. In Cambodia, the Vietnamese are a disliked, and often persecuted minority. Cambodians, including the Cambodian government, doesn’t care much about Vietnamese, or Vietnamese women, and in cities other than Phnom Penh, they live in their own parts of town. While these parts of town often do include brothels, Cambodians who always refer to prostitution in connection with the Vietnamese minority exaggerate the problem and are driven by racial animosity.