[Galadriel55]

Welcome aboard, Alowyn!

Aside from the passages already mentioned in the thread Inzil linked, I think these ones could beconsidered:

In the chapter The Stairs of Cirith Ungol (in The Two Towers), where Frodo and Sam talk about the "great tales" and how the characters do not enter stories deliberately, and that "they never end as tales". I think it's very inspirational, though it might be a tad too melancholic for a wedding.

Or, on a more silly note, you can re-write Bilbo's birthday speech (A Long Expected Party, Fellowship) into a wedding speech (ie take all of it and replace "birthday" with "wedding", and name changes to fit your family, a wedding announcement instead of the good-bye, and etc). It is something people would recognise if they read the books and/or watched the movies (I think the movie speech echoes the book one closely...), and it's filled with light and warmth, possibly the kind you're looking for. And there are some Rings involved too!