Arde is the Spanish word for "it burns". It comes from the verb arder, which means "to burn" or "to be on fire".
In "Me Prometí," Ivan Cornejo uses this powerful word metaphorically to describe intense emotional pain. He sings, "Arde tanto escuchar tu voz" (It burns so much to hear your voice), turning the abstract feeling of heartbreak into a visceral, physical sensation. It's a dramatic and poetic word you won't hear every day.
Ever had to give yourself a tough-love speech in the mirror? That's exactly what Ivan Cornejo is doing in "Me Prometí." He's literally telling himself to let someone go, starting with the blunt command, "Suéltala, no es pa' ti" (Let her go, she's not for you). It's a song about the promises we make to ourselves after a breakup—and how hard they are to keep. He admits he's tried to move on before, but this time has to be different: "Me tengo que ir... Y esta vez de verdad" (I have to go... And this time for real).
He's fighting his own desire to go back, reminding himself of the pain. He remembers how her voice "Era dulce hasta que mintió" (Was sweet until it lied) and how much it hurts to even hear it now. The whole song feels like an internal battle, a final, desperate attempt to convince himself to choose healing over a relationship that's clearly hurting him. He knows he needs to stop trying to escape the truth and finally start to "sanar" (heal).