plight (one's) troth

To bind oneself to another person in marriage. This archaic phrase, still sometimes used in modern writing for stylistic effect, employs the obsolete words "plight" ("to pledge") and "troth" ("truth"). There are some practical matters that people rarely consider when they decide to plight their troth.

plight your troth

pledge your word in marriage or betrothal.

The verb plight is now virtually obsolete except in this particular phrase, as is the noun troth .

plight (one's) troth

1. To become engaged to marry.

2. To give one's solemn oath.