The United States' Commitment to Not Admit Ukrane and Nata

I don't really understand what some kind of commitment or promise from the united states to not admit ukrane andto nata would really mean, why that would really be so valuable. From their point of view, aren't they looking at kind of unreliability of us? I think perhaps there's more of an imperial or colonial agenda than one that's about nado midon. But if we're talking about the shape of some kind of settlement which would satisfy both parties, i mean, what is going to happen with ucrane's trade policy in this scenario?