From a website of the Marionite Eparchy of St. Maron of Brooklyn
The prayer blessing the marriage crowns first develops the theme of crowning and creation, how flowers crown the earth, stars crown the heavens and the sea enriches the land. It also sees crowning as a symbol of divine vocation and speaks of holy kings, priests and prophets being crowned. In crowning the groom, the priest prays for God's blessing on him. When crowning the bride, the priest recalls the great women of the Old Testament and prays that she receive the crown of glory. He petitions that she be adorned with the fruits of the Spirit and "flourish as a blessed vine in the midst of the Church." The witnesses are crowned as representing the whole community which is partaking in the event of blessed joy.