Maybe say a little something about what she said to you the first time she told you about him and how she was beaming when she said it. Or a small personal story you know of that shows how wonderful they are for each other- nothing embarrassing, but endearing that will make people go "Awe!" I know how hard it can be to write something that you think would come SO easy. I just think that the more personal you can make it the better- because in all reality no one but the newlyweds will probably remember what you said the next morning. Just some thoughts. Good luck!!