Either Iran makes a deal to cease uranium enrichment and ensure it does not have nuclear weapons, or the absence of nuclear weapons will be imposed on the nation militarily. The U.S. wants to avoid death and destruction, but either way, the end result will be the same for Tehran.
Iran has no desire for nuclear weapons and is prepared to reach an agreement with the U.S. on this basis. However, Iran must maintain the right to enrich uranium for civilian purposes and this can be effectively monitored by inspectors from the International Atomic Energy Agency.
Iran has no real interest in reaching a nuclear agreement. It is simply buying time through the negotiation process to better protect its nuclear sites so that when strikes come, they will be less effective. It's imperative that strikes are carried out urgently.