Laberinto literally means "labyrinth" or "maze". It's a visually powerful word that you don't often hear in pop songs.
In "Amar De Nuevo," Rauw Alejandro uses it as a metaphor for his own complex emotions after being hurt. By singing "Soy un laberinto sin salida" (I'm a labyrinth with no exit), he's warning his new love that he's difficult to understand and lost within his own feelings, making him a challenge to love.
Ever been so hurt by a past relationship that you're scared to start something new? That's exactly where Rauw Alejandro is in this song. He's met someone amazing who makes his past disappear and reminds him how easy it is to laugh, singing, "Cuando tú estás cerca de mí / Se siente bien, mi pasado no existe" (When you're close to me / It feels good, my past doesn't exist). But he's still terrified of getting hurt again and admits he has major trust issues, telling her, "Baby, no confío en esto del amor / Porque mucho antes la he pasado mal" (Baby, I don't trust this love thing / Because a long time ago I had a bad time).
He's caught between wanting to fall for this new person and the fear holding him back. He asks her to be patient and teach him how to love again: "Enséñame a amar de nuevo / Mejor que antes" (Teach me to love again / Better than before). The song even includes a whole section where he talks to his ex, explaining how much she hurt him before declaring that this new girl is an "ángel llegó a salvarme" (an angel who arrived to save me). It's a song about the slow, scary process of healing and learning to open your heart one more time.