Braille refers to the tactile writing system used by people who are blind or visually impaired. It's a very unique word to find in a reggaeton song, making it instantly memorable.
In the lyrics, Cris MJ sings, "Ven y cáele, pa' leerte los labios en braille" (Come and fall for it, so I can read your lips in braille). This line uses the word metaphorically to suggest an intimate and sensual connection, implying he wants to know her so deeply that he can
"Braile" is Cris MJ working one seductive idea until it becomes the whole song: he wants to know a woman so well he could "leerte los labios en braille" [read your lips in braille]. The premise is a rescue mission dressed up as a pickup line. "Si ese cabrón te lastimó, el cora te dañó" [If that jerk hurt you, wrecked your heart] opens the track by naming the ex before naming himself, and every verse after that is Cris MJ promising to undo the damage with attention.
The fantasy escalates fast. He pictures marrying her at Casa de Campo "a lo Michael Jackson" [Michael Jackson style], then drops any pretense of subtlety in the bridge, calling himself set on taking her "pa' las Maldiva'" [to the Maldives] to make good on it. By the last thirty seconds the lyrics have stopped altogether, just ad-libs and a shoutout to his producer, "Dímelo, Reeli en los contr-" [Talk to me, Reeli on the controls]. The song was never really about the ex who hurt her. It's about how confident Cris MJ sounds pretending to fix it.