What is the main concern for Ukrainians regarding potential peace negotiations with Russia?

The main concern for Ukrainians is that if a peace deal is negotiated, Putin will simply bide his time and later return to take what he wants - similar to fears during the Vietnam War when Nixon worried North Vietnam would resume hostilities after U.S. withdrawal. Despite different circumstances (U.S. had troops on the ground in Vietnam but not in Ukraine), the fundamental security concern remains: without proper guarantees, an aggressor might temporarily retreat only to attack again when conditions are favorable. This comparison highlights the delicate balance between achieving immediate peace and ensuring long-term security in conflict resolution.