It may not be easy, but the only cost is your time and perhaps some headaches while you try to think of something that rhymes with thong. (Come to think of it, might be wise to swap in something else in that line.) Few writers can pull off a Shakespearean sonnet or metaphors like Wordsworth, so don't try. Go with the cute, silly and personal rather than broad, overly earnest sentiments. When you're satisfied with a final draft, handwrite it and put it in a picture frame. Alternately, if you're completely hopeless as a writer, handwrite her favorite poem or the lyrics to a song that means something to you as a couple (i.e., your wedding song).