Ilusionarme comes from the verb ilusionar, which means to excite, to fill with hope, or to create an illusion. When used reflexively as ilusionarme, it means "to get my hopes up" or "to delude myself."
In the context of the song, the singer is asking for clarity from their partner: "Que me quede claro para no ilusionarme que vas a volver" (Make it clear to me so I don't get my hopes up that you're coming back). It captures the vulnerability and emotional stakes of the relationship, making it a very relatable and poignant word.
Have you ever been in that frustrating spot where you just need to know where you stand in a relationship? That's exactly what Los Plebes del Rancho de Ariel Camacho are singing about in "Cómo Le Vamos A Hacer" [How Are We Going To Do It?].
The singer is tired of waiting and wants a clear answer: "si vas a quererme o si ibas a odiarme, dime de una vez" [if you're going to love me or if you're going to hate me, tell me right now]. He's even a bit blunt, saying, "sufrí por tu culpa y es un pasatiempo que lo recomiendo" [I suffered because of you and it's a pastime I recommend] – almost like he's sarcastically suggesting others try his heartbreak! He knows this isn't a simple fix, admitting "no creo que vaya a arreglarse con un solo beso" [I don't think it's going to be fixed with just one kiss]. It's a relatable feeling when you're just done with the back and forth and need a decision.