The Catechism in Questions & Answers

741. What is the significance of the wedding blessing?

The wedding blessing can have many different effects: it provides strength for enduring love and fidelity, promotes the willingness to serve, help, and understand one another, and it helps partners to forgive each other and reconcile differences. However, the blessing received can only take effect if the couple conducts themselves accordingly.

Acts of blessing, wedding blessing: see Questions 660. et seq., 671.