Quebrantos translates to "heartbreaks" or "misfortunes." It's a more formal and poetic word than common alternatives like problemas or penas, making it stand out in the lyrics.
In the song, Luis Miguel sings, "Usted es la culpable de todas mis angustias y todos mis quebrantos." He uses this word to express the profound sorrow and emotional damage caused by the person he's addressing, highlighting the depth of his suffering in a dramatic and memorable way.
"Usted" is a classic Mexican bolero, written by Álvaro Carrillo and made famous on Luis Miguel's 1991 album Romance. It plays on Spanish's formal "usted" (a distant, respectful "you"), using it for someone the singer is anything but distant from.
He blames her for every anguish and heartbreak he carries, yet calls her love his only hope and himself a helpless slave to it. He begs her not to toy with his feelings, even as he admits he would give his life just to kiss her. The formal address makes the confession sting more: he cannot even bring himself to speak to her plainly, though his heart is completely hers."