Obsequiarte means "to gift you" or "to present you with." It's a more formal and elegant way to say "to give you" (darte), making it stand out.
In this song, the word takes a dark and ironic turn. The singer, heartbroken and betrayed, declares, "Tendré que obsequiarte un par de balazos pa que te duela" (I'll have to gift you a couple of bullets so it hurts you). This shocking contrast between the polite verb and the violent act creates a memorable and impactful moment in the lyrics.
Okay, so "Ingrata" is a really intense song about a love gone wrong! The singer is absolutely fed up with their ex, who keeps coming back, trying to sweet-talk them with lines like "No me digas que me quieres" [Don't tell me that you love me]. But the singer isn't buying it for a second, saying "ya no te creo nada" [I don't believe anything you say anymore].
It's clear there's a lot of pain and a feeling of betrayal. The singer feels like their ex is just toying with their emotions, and their tears are "falsas" [fake]. There's a really strong moment where the singer warns their ex, "si puedo hacerte daño / Solo falta que yo quiera" [if I can hurt you / I just need to want to], which is pretty chilling. And that ending? "Tendré que obsequiarte / Un par de balazos / Pa que te duela / Y aunque estoy triste / Por ya no tenerte / Voy a estar contigo / En tu funeral" [I'll have to give you / A couple of bullets / So it hurts you / And even though I'm sad / For not having you anymore / I'll be with you / At your funeral] – wow, that's a dramatic way to say goodbye!