What Makes A Romance?

Recently, a friend and I had a conversation concerning movies that featured a growing relationship between a man and a woman and what really makes them a true romance. I mean there are a lot of films that have a love story up front and center but still they're not considered a romance. Examples that jump to mind are, Speed, Romancing The Stone, and The Mummy. Don't believe me? Google them.
So what makes one story an epic romance and the other an action story? Let's compare these two example...