In Vietnam, the engagement is a festive ceremony involving the fiance's and fianc�e's families, and arranged in advance by the parents. The engagement is considered very important, and in some areas, even more important than the wedding.
Well before the engagement day, each family chooses two representatives from their side. The representatives can be family members or friends, but are usually a married couple who have a happy family of their own. Although there are two representatives, the man is the one who actually does the representation, requesting for fianc�e's hand in marriage on behalf of the fiance's family, exchanging gifts, and controlling the flow of the ceremony.
In addition to selecting their representatives, the families get together to negotiate the dowry and a date and time for the ceremony. Traditionally, the date and time are chosen based on the fiance's and fianc�e's dates and hours of birth, but in a fast-paced society, such as that of the United States, it's usually a matter of convenience. So, almost any good weekend will do.
Several days prior to engagement day the fiance's parents prepare gifts to proffer to the fianc�e's family. These gifts include betel leaves and areca nut fruits (trau cau), wine, tea, husband-wife cake (banh phu the), sticky rice, other foods, and jewelry. They are placed in trays and wrapped in red plastic paper, with the belief that red will bring good luck. In addition to the other foods, a whole pig is roasted and placed in a large tray, to be carried to the fianc�e's home by two young men. Mean while, the fianc� is getting the ring ready, and the fianc�e, preparing herself for the ceremony.
On engagement day, the fiance's family bear the gifts to the fianc�e's home and is greeted by the fianc�e's family. Once everyone is inside, fiance's representative asks the other representative for the fianc�e's hand in marriage on behalf of his party. The fianc�e's representative graciously accepts the gifts and presents the fianc�e to her in-laws to be united. Together, the engaged couple prays in front of the family altar and asks their ancestor for approval. When the prayer is finished, the fianc� places the engagement ring on his fianc�e's finger.
Following the ring presentation, the representatives formally introduce their party's family members according to his or her family role. From this moment forward, the fianc� and fianc�e are official members of their in-law family, and should refer to their in-law family members by their respective roles--"dad", "mom", "uncle", "aunt", and so forth. The parents in return accept a new son or daughter into their own family. After the ceremony, the families celebrate the momentous occasion with a feast organized by the fianc�e's family. It is expected that half of the food gifts received be unwrapped and shared before the fiance's family leaves.
The day after the engagement, the engaged couple and their parents visit the neighbors, friends, co-workers, and relatives who could not attend the ceremony. They bring some betel leaves and areca nuts, tea and/or wines to spread the good fortune.
from http://www.tuvy.com