With the Three, the Swords are entering Binah, the fields of understanding, of
perception and realization, and they reveal the dark side of understanding - or the
truth behind the common saying that idiots are the happier people.
It is the curse of the Swords to be so clear and honest, to analyze what others prefer to ignore, to put in plain light what others hide in the dark. They are not like the Cups who are lucky when they understand themselfes, the Swords are the Mind and when understanding what they see, they dive into melancholy.
So the Three of Swords can talk of a painful realization, a hard decision that has to be made, the melancholy of Saturn when recognizing the unveiled truth. They also can stand for a disappointment, the loss of an illusion, or the detection of a treachery, a lie, a deceit.
Drive: Melancholy, facing up a painful truth
Light: Understanding, sobering, losing beautiful but false illusions
Shadow: Disappointment, pain, sadness, separation, sorrows