Descarado translates to "shameless" or "cheeky." It's a vivid word that describes someone who acts without embarrassment or concern for others' opinions, often in a bold or impudent way.
In the song, the artist uses it to describe his own behavior, saying, "Qué descarado, perdón si te he decepcionado" (How shameless, sorry if I've disappointed you). This word perfectly captures the song's theme of a charming but commitment-phobic individual who is upfront about his intentions, even if they might disappoint others.
Sabino's "Pregúntale a Mis Ex's" is a hilariously blunt warning from a guy who knows he's not cut out for a serious relationship. He's upfront about it, telling anyone looking for something real, "No busques algo serio que yo soy muy mal quedado" [Don't look for something serious, I'm really bad at sticking around]. He even jokes about being a "jardinero de tanto que voy plantando" [gardener because of how much I go planting], which is a pretty funny way to say he's not settling down.
He's not trying to trick anyone; he'd rather you know his deal before things get complicated. He admits, "No me tomes en serio que yo soy para un ratito" [Don't take me seriously, I'm just for a little while], and if you're dreaming of a "principito" [prince charming] and a perfect relationship, he's quick to say, "Dale calma, nena, porque así no es" [Calm down, baby, because that's not how it is]. And if you don't believe him? Well, he suggests you just "Pregúntale a mis ex's" [Ask my exes]! It's a catchy, honest, and pretty funny take on avoiding commitment.