One way of thinking about the Israel/Iran/U.S. conundrum is to reverse the positions and see how they look to the other folks.
Except, perhaps, for Iran's professed desire to obliterate Israel, their aim of becoming a nuclear state, even including weapons, is really no different or illegitimate from the U.S. or Israel, which already have them. Therefore the basis for the U.S. and Israel seeking to prevent Iran from doing what they have already done is simply a defensive gesture, which is based not on issues of precedent or fairness but simply on our wishes and our potential power to enforce those desires.
For obvious reasons, trust based on past behavior cannot be used in this situation. There are many more reasons to distrust Iran than to trust them. Now look at that backwards. How can we ask Iran to trust us or Israel? They see what we have done in history, and deep down they probably are not only envious but also seriously afraid of the U.S. and Israel. And if the impasse cannot be broken, they do run a risk of being hit hard in various ways, which surely is why they are at the table now.
We say we abide by nonproliferation and inspections. They say: Big deal! You already have it! So what?
If Iran had ever said that obliteration of the U.S. was a prime goal, we surely would be even more stressed than we are now, and any effort to find a way out of the impasse we have now would for sure require a recant of obliteration.
Yes, that would only be words. And, yes sticks and stones can break my bones, but words? Never!
Therefore "trust and verify constantly" are the crux of any solution. That is true for all the parties to any Iranian deal.
All three parties, and their respective partners, benefit the world and themselves by toning down the rhetoric and eliminating unnecessary threats even though they may simply be noise.