Ilusionarme comes from the verb ilusionar, which means to excite, to fill with hope, or to create an illusion. In this context, it means "to get my hopes up" or "to delude myself."
The singer uses this word to express the danger of falling back into an old pattern. He sings, "Volvería a ilusionarme en lugar de olvidarte" (I would get my hopes up again instead of forgetting you), highlighting the painful cycle of false hope and disappointment in a toxic relationship.
This song is a classic tale of knowing better but still feeling that pull! Our singer is in a tough spot, admitting, "Te dijera que sí / Porque aun te sigo amando" [I'd tell you yes / Because I still love you]. But even with that love, they're smart enough to see through the other person's intentions, saying, "Pero ya tengo bien claro / Que te quieres divertir" [But I'm very clear now / That you just want to have fun]. It's that painful realization that the person they love doesn't want a real relationship, just a game.
They know if they give in, it'll only lead to more heartache. The lyrics are pretty direct: "Pero es un hecho que me vas a lastimar / Si te doy el acceso de nuevo a mi vida / Volveré a llorar" [But it's a fact that you're going to hurt me / If I give you access to my life again / I'll cry again]. It's a powerful moment of self-preservation, even when their heart is still very much involved. They sum it up perfectly with, "Tú no me quieres bien / Me quieres pa' jugar" [You don't love me well / You want me to play]. It's a sad but honest look at a love that's just not meant to be, unless, as they say, "Si supiera que nunca más te alejarías de mí / Te dijera que sí" [If I knew you'd never leave me again / I'd tell you yes].