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Only a few people remain believers of president Putins word.
No one cares what Putin or Zelensiy or Trump want, it's what they can get. Situation on the front leaves no doubt that Russia can take Donbas with time. If US can reach agreement that Russia will stop there and won't continue further, then why waste more souls and billions for the same outcome?
Most people were conditioned not to believe Putin's word. But non of that matters. What matters are agreements, and the consequences of pulling out of them. If it's more beneficial for a country to break an agreement I'd argue that the president has obligation to go against his own word if it's in the best interest of his country.
The whole unclassified conversation between Gorbachev and James Baker (US secretary of state) is interesting to read to get an idea how these agreements are happening now behind the closed doors. But here's an excerpt relevant to believing to someone's word
We fought a war together to bring peace to Europe. We didn't do so well handling the peace in the Cold was. And now we are faced with rapid and fundamental change. And we are in a better position to cooperate in preserving peace. I want you to know one thing for certain. The President and I have made clear that we seek no unilateral advantage in this process.
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We understand the need for assurances to the countries in the East. If we maintain a presence in a Germany that is a part of NATO, there would be no extension of NATO's jurisdiction for forces of NATO one inch to the east.
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For France and for Britain the question is whose going to be the major player in Europe. We have it easier. We are big countries and have out own weight. We also see how Kohl and his team are talking to us -- very carefully knowing what our two countries mean. So it is important to channel this process, while recognizing the sensitivities and being tactful.
And we all see what NATO has been doing since then and why Georgia and Ukraine became the hottest points, and the value of politicians word.