6. Sam and Molly
In Ghost, Sam and Molly are deeply in love with one another until one day, coming back home from a late-night movie, tragedy strikes.
Sam becomes a ghost quite early on in the movie as the plot is about him trying to protect Molly and keep her safe from danger as nasty people threaten her safety.
Even though they're separately and in 'different worlds', they find ways to communicate and reach each other as their love continues to live on.