Desempeño translates to "performance" or "execution". While it can be used in many contexts, its use here in a romantic setting makes it particularly interesting.
In the song, the lyrics say, "hasta hoy que yo probé tu desempeño en el amor" (until today that I tasted your performance in love). This line playfully and somewhat boldly describes experiencing a partner's romantic or intimate
El Guerillo tells the spirited tale of two best friends who stumble into romance after a night of laughs, music, and one drink too many. The singer confesses that love at first sight never worked for him, yet suddenly he realizes his closest companion is exactly what he has always dreamed of. Even though he knows crossing that line could risk their friendship, the pull of the moment is stronger than his doubts.
What follows is a joyful pledge of lifelong devotion. He celebrates how their relationship now blends friendship, passion, and destiny into something that feels perfect for both of them. The chorus repeats his promise to love her “for eternity,” highlighting the thrill of discovering that the perfect partner might have been right beside you all along.