If you know a happy couple who's about to walk down the aisle, consider yourself in good company. About 2.4 million people tie the knot each year in the U.S., with an average guest list of about 175.

Whatever type of card you’re writing, it can sometimes be tricky to come up with the right words to say. When coming up with what to write in a wedding card to newlyweds — which is a card given to the ...