I should also consider the academic sources: literature on love and death, cultural studies on ghost symbolism, psychology of grief. Maybe include Freud's concept of the return of the repressed, as ghosts can represent repressed emotions. Jung's shadow self might also be relevant. In Mexican culture, the blend of indigenous beliefs with Catholicism regarding death could be pivotal. How does this affect the portrayal of love's shadow?

Assuming you're referring to the movie "Ghost" or a related title:

A murdered man seeking justice and a final way to tell his partner he loves her.

The film won two Oscars—Best Supporting Actress and Best Original Screenplay—and was the highest-grossing film of 1990.