Pilate's job is to protect his government and he wants to know if this man Jesus is a threat to peace and stability.
Jesus responds that he is not the kind of king that Pilate has been trained to watch out for. He doesn't have an army, for example.
Pilate asks again: Are you a king? Jesus responds "That's what you say," then adds some remarks that I think would have been unintelligible to Pilate:
For this I was born, and for this I came into the world, to testify to the truth. Everyone who belongs to the truth listens to my voice.And, isn't it hard to understand how truth can prevail without having an army? without being a threat to powerful people? How can we defend ourselves against truth, anyway?
After all, Jesus didn't say that his followers were going to withdraw from the world. He said that it wasn't the world that gave him his authority.