Si Dios Perdona is a breakup duet where one person begs and the other has already packed their bags. Juliana opens by admitting "no soy perfecto" (I'm not perfect), then offers a cheeky defence: "nadie lo es en los primeros intentos" (nobody is on their first tries). She asks her partner's heart not to be "malito", a cute diminutive of "malo" (mean), and to forgive her. The hook is the whole argument in one line: "Si Dios perdona, ¿por qué tú no?" (If God forgives, why don't you?). It is a bold comparison, and a little bit manipulative, which is part of the fun.
Then Pipe Bueno answers, and he is not having it. "Juro que mil veces lo intenté" (I swear I tried a thousand times), he says, "pero hasta el perdón se desgasta con los años" (but even forgiveness wears out over the years). He wants to let his heart "se cure solito" (heal on its own) and find another love. Listen for "a la izquierda de mi pecho" (on the left side of my chest), a very Spanish way of pointing at the heart without naming it.