Suplicarás means "you will beg" or "you will plead." It's the future tense of the verb suplicar.
In the song, David Bisbal sings, "Todo empieza aquí, suplicarás que llegue el fin." This line, "Everything starts here, you will beg for the end to come," creates a dramatic and intense image, suggesting a powerful, overwhelming experience that the listener will want to last forever, or perhaps, be so intense they'll beg for it to end. It's a strong, evocative word that stands out.
"Mi Norte Es Tu Sur" turns geography into a love metaphor and never lets go of it. Bisbal casts himself as a compass whose direction has changed hands: "Hoy mi norte tiene dueña, tiene rumbo y verso" ("Today my north has an owner, has a course and verse"). Whatever bearing he used to follow now points at her.
The chorus builds the whole song around a pun on "sur" (south). "El temblor que se va, el huracán que se irá, se va al sur" ("The tremor that is leaving, the hurricane that will leave, is going south") turns restlessness into something with a destination, and the verses keep it physical: "Cada palmo de piel, cada gota de miel, sabe a sur" ("Every inch of skin, every drop of honey, tastes like south"). "Bésame, piérdete" ("Kiss me, get lost") is the whole plan in four words.