That straightforward honesty allowed for some golden entertainment at the expense of the king. He's corrupt and deserves punishment to say the least, but our power couple is also basically untouchable to him so he ends up being a laughingstock for the readers instead.
I appreciate that he's not truly stupid and is aware since the beginning that the king has been trying to get him killed. Considering that he's both emotionally broken and ridiculously overpowered enough to be unaffected, I'll excuse his lack of desire to take revenge on the king who has been betraying him. He'll probably get his comeuppance at the hand of the hero's growing family instead.