Perhaps the most effective way to develop this paragraph is to combine the details of your various sentences into a more fluidly-devised narrative.  For example, you could say:

"As a resident of Heaven, George MacDonald appeared in this chapter as a guide.  George told the main character that as long as people chose to stay, the grey town would be Hell.  Those people he saw who would rather stay in Hell he considered selfish, which makes sense to me.  Hell, in some ways, is never Hell.  It depends on the resident.  Hell was grey and empty because the people who lived there were selfish."

As a paragraph, there are a number of areas where you can expand on your thoughts.  For example, when you indicate that these thoughts make sense to you, explain how they make sense to you.  In addition, you can explore the relativity of Hell.  If Hell depends on the resident, perhaps you can indicate some instances where a Hell for some would not be a Hell for others.  Ultimately, the most effective way to develop your thoughts here is to fully explain your perspective on the subject matter.