La neta is a very common slang term in Mexico that literally translates to "the truth" or "the net". However, it's used more like "honestly" or "for real" in casual conversation.
In this song, the singer uses it to emphasize his sincerity and directness when expressing his feelings for the woman he's singing to. He wants her to know he's being completely honest about his love and desires.
Have you ever been so smitten with someone that you just want to lay all your cards on the table? That's exactly what Los Del Limit are doing in "La Neta." The singer is completely captivated, telling this woman, "Hola, mujer, yo quiero saber de ti" [Hello, woman, I want to know about you]. He wants to know her dreams so he can live them with her! How sweet is that?
He's super direct, admitting, "Yo la quiero para mí" [I want her for myself] and "Yo la quiero hacer feliz" [I want to make her happy]. He might not be perfect, but he sees her as his whole world: "tú eres mi universo" [you are my universe]. The chorus is so catchy and honest, with him saying, "Y es que tú me gustas de pies a cabeza / Eres muy perfecta, mi hermosa princesa" [And I like you from head to toe / You are very perfect, my beautiful princess]. He even invites her for a beer and promises to "bajarte una de ellas" [bring you down one of them] referring to the stars. He's just waiting for her to "dime la neta" [tell me the truth] about how she feels. It's a really charming and straightforward love song about being head-over-heels!