Ilusionaste comes from the verb ilusionar, which doesn't have a perfect one-word translation in English. It means 'to get someone's hopes up' or 'to make someone dream' about a potential future.
In this song about heartbreak, the singer asks, "¿Por qué me ilusionaste con tus besos?" (Why did you get my hopes up with your kisses?). He feels like he was led to believe in a love that wasn't real. It's a beautifully nuanced word that captures the feeling of being promised a dream that was then taken away.
This song is a classic story of a relationship that started out hot and then went cold. Eslabon Armado sings about how things used to be amazing, remembering when his girlfriend "siempre te acostabas en mi pecho" (always used to lie on my chest). But now, everything has changed. Her friends are telling him to leave her, and he notices that "ya ni con rosas te hace contenta" (not even roses make you happy anymore).
He gets to the heart of the problem when he sings, "Yo no te di un castillo ni un anillo de un millón / Pero sí te di mi tonto corazón" (I didn't give you a castle or a million-dollar ring / But I did give you my foolish heart). He feels like his love wasn't enough and that she took advantage of him. The most painful part is the waiting. He watches a full day pass, "veinticuatro exacto" (exactly twenty-four hours), waiting for a message that will never come, because he realizes, "ya sé que me bloqueaste" (I already know you blocked me). It's a very modern and direct way to describe a breakup.