This one is not easy.  Without a doubt, Wiesel's work is one of the most painful accounts of the Holocaust.  There is little in it that is designed to be positive or hopeful because it was a time period in which both elements were in staggeringly short supply.  Yet, I think that the French Girl who tends to Eliezer after Idek beats him up would be representative of a theme of hope.  It is revealed that if she speaks or acknowledges Eliezer, she probably would have been killed. Yet, she takes care of him, tends to his wounds when few others would have.  Her sacrifice is one of the few moments where it is evident that there can be redemption in some of the most dire of circumstances.  In doing so, there is an embodiment of hope in the narrative.  Overall, I am not certain that there will be much in way of hope because some of the primary thematic implications of the work is to present a setting where the ramifications of a world without hope is evident.  It is here where I feel that there is going to be a struggle to find such entities.  However, the girl that tends to Eliezer would represent such a notion in a condition where much like it is lacking.