Subestimar means "to underestimate." It's a strong verb that implies misjudging someone's capabilities or intelligence, often with negative consequences.
In the song, the singer admits, "Nunca intenté subestimar tu inteligencia" (I never tried to underestimate your intelligence). This line reveals a moment of regret and self-awareness, as the singer reflects on past mistakes in the relationship. It's a word that adds depth to the narrative of betrayal and misunderstanding.
Camila's song "Mía" is a really honest look at a relationship that went wrong, told from the perspective of someone who thought they had it all figured out. He admits his biggest mistake was "Haberte dado por hecho" [taking you for granted], and maybe even believing in her innocence. He also confesses to lying, saying "Sé que haberte mentido fue lo peor" [I know lying to you was the worst thing].
But it's not all self-blame! He starts to notice something shift, an energy change, and that her gaze "dejó de brillar" [stopped shining]. The title, "Mía" [Mine], is what he thought she was, but he eventually discovers her heart was "incompleto" [incomplete]. He even saw her "deseándolo en silencio" [desiring it in silence], realizing she was never truly his. It's a pretty intense song about realizing you've been played and the sting of that betrayal.