Despojarme comes from the verb despojar, meaning 'to strip', 'to divest', or 'to dispossess'. The reflexive form despojarme means 'to strip myself bare' or 'to give everything up'.
In the context of the song, the singer uses it to express the profound extent of his emotional investment in a relationship. He laments, "Darlo todo hasta despojarme / Para una persona que no era la mía" (To give everything, even stripping myself bare / For a person who wasn't mine). This word powerfully conveys the idea of complete self-sacrifice and vulnerability in love, only to be met with disappointment.
Darío Gómez's "No Hay Derecho" is a classic despecho (heartbreak) anthem, where he's just fed up with love gone wrong! He kicks off by saying, "No hay derecho, de ti enamorarme / Para equivocarme en lo que más creía" [It's not right for me to fall in love with you / To be wrong about what I believed in most]. He gave his all, only to realize this person wasn't the one for him.
He feels like fate played a cruel trick, always pairing him with the wrong person. He laments, "Ahora me doy cuenta que ni te pareces / A los sentimientos que de ti esperé" [Now I realize you don't even resemble / The feelings I expected from you]. It's a blunt realization that the person he loved wasn't who he thought they were, and he's pretty upset about it. He even says, "Tú perturbaste mi mente / La falsedad te vendió" [You disturbed my mind / Falsehood sold you out], suggesting he was deceived. He's left feeling like his luck is unfairly punishing him, and he regrets letting this person into his life at all.