#14 looks like the best so far, I like the silver look and the balance between the hearts and the text, and the hearts suggest wedding rings.
The concept of the chat balloons is interesting in #16, but I think it conveys more of a "casual dating" attitude rather than the "serious about marriage" attitude that we want.
#18 has a very nice concept but it seems that the heart design is much "heavier" than the text so it looks unbalanced. Maybe if it looked a little lighter in weight like the hearts in
#14?