Perteneces comes from the verb pertenecer, meaning "to belong". It's a key word in this song about moving on from a relationship.
The song opens with the line, "No te esperare si no tu no me perteneces" (I won't wait for you if you don't belong to me). This sets the tone for the entire song, highlighting the theme of independence and the realization that the other person is not truly theirs, making it a powerful and central word.
Matt Hunter builds "Juro Que" around a breakup he's trying to talk himself into believing. He opens flatly, "No te esperare si no tu no me perteneces" ("I won't wait for you if you don't belong to me"), then spends the rest of the song repeating the promise that gives the track its title: "Juro que puedo olvidarte" / "Juro que no va a afectarme" ("I swear I can forget you" / "I swear it won't affect me").
The insistence is the point. He admits "Aunque extrañe cada parte" ("although I miss every part") in the same breath as the vow, and by the bridge he's rationalizing it outward — "Si en el mar hay mas peces mejores" ("if there are more fish in the sea, the better") — before landing on the line that actually closes the door: "No tiene sentido reintentar" ("there's no point in retrying"). It's less a song about being over someone than about the exact moment of deciding to be.