Nicky Jam opens this one almost like a confession: "Desde que te conocí... yo no soy el mismo" (Since I met you... I'm not the same). He stopped doing the same old things, "Nada de eso" (None of that), and the whole song is him admitting he got caught off guard by love.
The chorus is the big promise. "Niña, te juro volví a nacer" (Girl, I swear I was born again) is a common Spanish way to say someone changed your life, and "Seré fiel a tu piel" (I'll be faithful to your skin) is a neat twist on "I'll be faithful to you": he is loyal to her body, her touch, all of her. It rhymes, it sticks, and it is a little cheesy in the best way.
The verses tell you what changed. "Hasta la calle por ti yo he dejado" (I've even left the streets for you) means he gave up the street life, the partying and running around, for her. People say he's "amarrado" (tied down, whipped), and his answer is a shrug: "No importa, en mi vida tú lo eres todo" (It doesn't matter, in my life you're everything). Great song for picking up love vocabulary and the very useful "volver a" + verb, meaning to do something again.