Frontear is a Spanish slang term, particularly common in urban and reggaeton music, that means "to show off" or "to flaunt". It's derived from the English word "front" in the sense of putting on a display.
In the song, Dalex sings, "Para que vaya a frontear" (So you can go and show off), referring to the expensive Mercedes he bought for his partner. It highlights a common theme in the genre of displaying wealth and status.
Dalex's "Sola" is a bold declaration of new love and unwavering protection. Our singer tells his new partner, "Te dije que te quiero para mí toda la vida" [I told you I want you for me all my life], emphasizing that he found her when she was "perdida" [lost]. He assures her repeatedly, "Tú nunca vas a estar sola" [You're never going to be alone], promising to be by her side.
He makes it clear that her past relationship is over, stating, "Que contigo el ya no joda" [That he doesn't mess with you anymore], and proudly proclaims, "Que ahora soy yo el que a ti te desviste" [That now I'm the one who undresses you]. He's all about spoiling her, mentioning a "mercedes tintada que te acabo de comprar" [tinted Mercedes I just bought you] and assuring her, "No te preocupes que nada te va a faltar" [Don't worry, you won't lack anything]. It's a confident, almost possessive, promise to keep her happy and secure, with a bit of a bad-boy edge.