You could say how much you appreciate and love her and that you’re happy for her and her husband. You can praise her as a daughter and express confidence that she’ll make a good wife. Mention the good things in life you wish for her such as love.
You may also share a few words of wisdom by encouraging your daughter and her husband to rely on and communicate with each other. Ask them to be honest when they are wrong and humble when they are right. Some humor may be appropriate. Congratulate your daughter and new son in law on their union.