Cíñelas comes from the verb ceñir, which means to gird, encircle, or embrace. It's a less common verb in everyday Spanish, making it stand out in the lyrics.
In the song, the artist sings, "Y entre todas las estrellas tu cíñelas la mas bella" (And among all the stars, you encircle the most beautiful one). Here, it's used poetically to suggest that the beloved is so beautiful that she outshines and encompasses all other stars, making her the center of attention and admiration.
Nyno Vargas's "Esa Morena" tells a sweet story of young love and the challenges that come with it. Our singer is head-over-heels for a girl from his neighborhood, a "morena" [brunette] he's been dreaming of since they were kids. He wants to be with her, to hold her in his arms, but there's a big problem: her family doesn't approve!
They think he's a night owl, always out, with too many women, and always drinking. But he insists his love is "puro" [pure] and "verdadero" [true]. He remembers seeing her in the neighborhood, beautiful as always, with her hair down and Versace perfume. He was always too shy to talk to her, especially with her mom or friends around, but he loved her smile and how she got nervous when he looked at her. Now, he's begging her to stay with him, to ignore her family, and to think about "nosotros" [us]. He wants to take her to the sky and share a star, promising she'll never regret being with him. It's a classic tale of forbidden love, with Nyno Vargas pouring his heart out for his childhood sweetheart.