When you're looking for synonyms for the phrase "commitment ceremony," there are a few different options to choose from. One common phrase that's often used is "union ceremony," which highlights the coming together of two individuals in an act of commitment. Another option might be "dedication ceremony," which focuses on the devotion and loyalty that the couple has to each other. A third synonym that's sometimes used is "vow exchange," which emphasizes the promises and pledges that the couple makes to each other during the ceremony. Regardless of the specific phrase that's used, the important thing is that the couple is taking a meaningful step towards solidifying their relationship and expressing their commitment to one another.