One of my absolute favorite romantic comedies has to be a lovely movie called, "The Sea Change" starring Sean Chapman (who played Frank Cotton in the horror/thriller "Hellraiser"), Maryam D'Abo, and Ray Winstone (The Departed, Sweeney Todd, The Final Cut, King Arthur).
I came across it accidentally while searching google for other movies which British-born actor Sean Chapman also starred in. I ordered the DVD on Amazon.com, but since then found the full movie free on a site called Sockshare.PM. I highly recommend watching it if you are a lover of romance and mermaids!
If so, here is the direct link for this movie:
"Why did the sailor jump into the water? To be with the mermaid!"