Verbal irony is a statement that seems to contradict itself.
Irony is basically when words are used in an unexpected way. Verbal irony means that a phrase involves words where words with opposite meanings are used, such as “clear as mud.” For example, the idea that a king could be “semi-barbaric” is verbal irony because you are either barbaric or you aren’t. Another good example of verbal irony is “the rhapsodies of dying gladiators.” This is because “rhapsodies” are cries of joy, and someone who is dying cries out in pain, not joy. Then of course, there is “crooked straight.” The description of the king’s justice ends with a nice bit of verbal irony.
The decisions of this tribunal were not only fair, they were positively determinate: the accused person was instantly punished if he found himself guilty, and, if innocent, he was rewarded on the spot, whether he liked it or not.
This is ironic, of course, because he is rewarded "whether he liked it or not."
The point of all of this verbal irony is that the king thinks that he is creating this perfect system of justice, where the truth is found and there is no human hand in it. However, ironically (and this is a situational irony and not a verbal irony), the winner is actually found by luck and not by whether or not he actually was guilty or innocent. He either chooses one door or the other. He has a fifty-fifty chance. It’s a coin toss. Unless you believe in divine-intervention, which this semi-barbaric king does not, there is no guilt or innocence being determined.
Irony abounds in this story, and perhaps most in the fact that it has an ambiguous ending. How you think it ends tells something about you—perhaps. It is a psychological instrument. If you think the lady betrayed her lover, that might tell more about you than about human nature.