Answer:
It is called the trail of tears because Native Americans were being forced from their homeland by the settlers and forced to move to the west, and they called this the trail of tears because of the horrible effects and experiences they had on the way there. These hardships included death, starvation, and horrible disease. Not all hardships were physical though because they were obviously very upset about leaving their homeland.
(You could also say that they were upset because their homeland was a very important part of their culture, but that is up to you.)
Hope this helps!