1. The actual or genuine cause or explanation for something, as opposed to a false or superficial one
The true reason for his absence was that he was ill.
A verdadeira razão da sua ausência era que ele estava doente.
2. The real motivation or underlying cause behind an action or statement
We finally discovered the true reason behind her resignation.
Finalmente descobrimos a verdadeira razão por trás de sua demissão.