Tentador means 'tempting' or 'enticing'. It's a word that evokes a sense of desire and allure, making it quite engaging.
In the song, Humbe sings, "Que volver a vernos sea algo tentador" (May seeing each other again be something tempting). He uses this word to express his hope that the idea of reuniting with his beloved is so appealing that they can't resist, adding a romantic and slightly playful touch to his longing.
"Amor de cine" is about falling for someone so hard it feels unreal, like something out of a movie. The singer admits he's nervous, can't stop thinking about her, and is happy to be at her call at any hour.
He promises to give her all the time and attention she needs, to chase away her sadness, and to fill her days with reasons to smile. The chorus keeps circling back to the idea that together they become one, and then two again, a playful way of saying they complete each other.
By the bridge he's making bigger promises: he'd sell his soul, run barefoot for miles, give everything, just to make her his. It's romantic exaggeration on purpose, the kind of over-the-top devotion that only makes sense when a love feels as big as a movie.