This is the basic dictionary definition of "to marry", if that's what you're wanting.

If you marry someone, you take them as your wife (if you're a man) or husband (if you're a woman). "Spouse" is the gender-neutral word for husband or wife.

Basically, the guy wants to formally and publicly declare his lifelong love and commitment to the woman he loves. They will do this in a special ceremony. Virtually every culture recognises marriage and has some kind of ceremony for it. In Western culture, it's traditional to get married in a church, but these days people get married in all sorts of places and in all sorts of ways. Although an increasing number of people are living together without getting married, it's still pretty popular.

Once the ceremony is over, the couple will sign a register and be recognised by the law as husband and wife.

The word "marry" can also sometimes be applied to the celebrant (usually a priest or minister of some kind, but can be a Justice of the Peace) who does the ceremony. E.g. John and Jane were married by Reverend Smith - Rev. Smith conducted John and Jane's wedding ceremony.

Here though I think the meaning "take as a spouse" is definitely what is meant.

Hopefully my explanation will have helped, although for a word like this, looking up your own dictionary should suffice, really.

not that i disagree with the above...