Freedom from attachments to the five aggregates of attachment is the end of suffering. This freedom is not conditioned by causes, as are the conditioned states: Nibbana is the non-attachment to conditioned experience.
To understand the unconditioned, we need to see for ourselves that everything that has a nature to be born has a nature to die: that every phenomenon that has a cause is impermanent. By letting go of attachment to desire for conditioned phenomena, desire can come to an end and we can be liberated from suffering.