What does Elie Wiesel mean when he wrote that illusion ruled the ghetto?

Answer 1

Maybe because the ghettos were some sort of "trickery", because life at first was simple and in the ghettos it didn't seem real. Or the German soldiers were playing tricks on them, like for example the Germans were friendly at first and no one thought the cruelty was just a rumor, then all of a sudden they turned around and became ruthless.

Answer 2

Elie Wiesel is referring to the false hope and delusions that people in the ghetto clung to in order to cope with their unbearable situation. Their belief in these illusions provided a sense of comfort and distraction from the harsh reality of their circumstances.