karamba : I can probably answer your question since I’m part Vietnamese and my sister just got married a few years back with this dilemma. Are you doing the morning tea ceremony and the reception?
Usually for the morning tea ceremony you are supposed to put money, gold, and whatever you want to gift as a dowry in those red containers during the procession to the bride’s house. Some stuff I’ve seen is a land deed (rarely), car (not as common anymore), money, gold, fruits, and traditional desserts. The boxes come in a set number. The amount and value of the gifts can be agreed upon by both families beforehand.
A lot of modern couples who don’t plan to give a lot or assets like houses or cars actually put some stuff in the boxes just to “show off” to the neighbors. It gives the girl’s parents a chance to brag about “how much their daughters are worth.” Though if you do this, it’s usually very clear and agreed upon by the parents that this is not a gift, but in essence on loan just for show. This is still quite radical thinking by the way, so not many people accept it or agree with it.
The morning ceremony has two parts, one is taken place at “your house” and one at her house. It’s pretty much a prcession from your house to her house, do a ceremony and snack at her house before you take her back to “your house” for the second part of the ceremony and then brunch. You are supposed to cover for the ceremony at your house plus the brunch, and the bride’s family cover for theirs. There are some which opt out for the symbolic procession to and from houses, usually because they’re doing it at a destination wedding or such, then in that case the groom’s side covers for it.
For the reception, there’s usually no physical gifts, only money in the envelope. Those goes to covering for the catering and reception costs. If one of the set of parents paid for the reception, they get the envelope money, if the couple pay for it, you guys get it. Sometimes one or both parents will pay for the reception and give that money as a “newlywed” fund for the couple, depending on their generosity. I’ve actually see some parents demand the envelope money without helping pay for the reception. I don’t know if it is right, but generally people look at this behavior as kind of greedy…
With foreigners especially, some parents might try to take advantage of you if they think you’re rich, so just make sure you, or your wife talks to them properly and makes sure they understand who’s paying for what. Let me know if you need help.