Taller literally means "workshop" or "repair shop." It's an interesting word choice because it's not typically found in romantic or emotional songs.
In the lyrics, Danny Ocean sings, "Este corazón no funciona, hay que mandarlo al taller" (This heart doesn't work, we have to send it to the workshop). He uses this word metaphorically to express that his heart is broken and needs to be fixed, treating it like a broken machine. This unexpected and creative use of taller makes it memorable and adds a unique twist to the song's emotional narrative.
"NO ES AMOR" is Danny Ocean singing to someone he keeps hurting, even though he cares about them.
He admits he has gotten used to lying and pulling away, and he keeps asking himself why he treats this person so badly. Each chorus is an apology, "lo siento mucho, amor," but the sorry never quite fixes what he did.
The title line is the point he lands on: if he can hurt someone this often and this easily, whatever this is, it is not love. He says he does not want to go back to those old places in his heart, which reads as a promise to himself as much as to her.