I N take thee M to my wedded husband, to have and to hold from this day forward, for better for worse, for richer for poorer, in sickness and in health, to love, cherish, and to obey, till death us do part, according to God's holy ordinance; and thereto I give thee my troth.
Book Of Common Prayer, The. Solemnization of Matrimony, "Betrothal," (1662).
"N" and "M" refer to "name" and "names" respectively, standing for the Latin nomen and nomina (rendered as "M," for two "N's" contracted). In general practise, the man promises only "to love and to cherish" his wife and uses the words "I plight thee my troth."