Desire begins when you perceive a world out there, and the world makes a promise. What does the world say? ”Here you will get what you want.”
You cannot desire in absence of a promise. This is the fundamental duality of mind. You desire only because you are hopeful that the desire will be fulfilled some day. Hoping and incompletion go together. Only because you feel incomplete do you hope for fulfillment.
And we are still desiring. That is the proof that nothing has ever kept its promise.