Everyone knows Trump lies all of the time. On occasion, he does it to deceive the public; sometimes he thinks it creates leverage; sometimes he does it to pump himself up; every now and then, he wants to force his supporters to prove their loyalty. The bottom line here is that nothing he says about the war can be trusted; his actions will speak much louder than his words.
But the Iranian regime lies, too. It needs to prove to its subjects that their suffering has been worth it. As a result, it makes statements about the negotiations and potential agreements that no reasonable person can believe, as they do not reflect the actual conditions on the ground. Its actions will speak louder than words, too.
The ultimate outcome of the negotiations, if they succeed, has been known for months. The only real questions involve a few of the details, particularly about the treatment of the nuclear material. Both sides will have to be able to spin an agreement as a victory; in Trump’s case, he will also have to make a plausible argument that he didn’t make an Obama deal. The need to save face is the real sticking point in the negotiations–not the contents of the deal itself.