The phrase "marry into" refers to the act of marrying someone who belongs to a certain group or family. However, there are various other synonyms for this phrase that you can use in your writing. Some common alternatives include "wed into", "join in matrimony with", "tie the knot with", "unite in marriage with", "take as a spouse from", "form a union with", "merge via marriage with" and "become a member of through marriage". Therefore, you can experiment with these phrasings to make your writing more interesting and engaging.