Torpe translates to "clumsy" or "foolish." While it can describe physical clumsiness, in this song, it's used to describe the heart's inability to discern true love from deceit.
The lyric "Mi corazón tan torpe que no supo distinguir" (My heart so foolish that it couldn't distinguish) powerfully conveys the singer's regret and self-blame for being blind to his lover's insincerity. It's an emotionally charged word that highlights the pain of betrayal.
Ulices Chaidez's "Yo Te Creí" is a really relatable song about realizing you've been completely fooled in love. The singer talks about how he used to say 'te amo' [I love you], and his partner wouldn't even respond, just silence him with a kiss and look down. He thought it was shyness or just her personality, but now he sees how 'estúpido fue imaginar que te importaba' [stupid it was to imagine that I mattered to you].
He curses the moment he fell in love, because she said 'exactamente lo que yo quería oír' [exactly what I wanted to hear]. He gave her everything, and he's shocked by how she repaid him. His heart was so 'torpe que no supo distinguir' [clumsy that it couldn't distinguish] between real love and what she gave him. It's embarrassing for him to admit he adored 'a alguien que no vale nada' [someone who is worth nothing]. It's a powerful song about the sting of betrayal and the regret of trusting someone who didn't deserve it.