Is "the single story" in reference to something that Chimamanda Ngozi Adichie said? What do you mean by single story?
Adichie said (I believe in her TED Talk) that the single story is dangerous because we cannot afford to only hear one story from one person in a country. Basically, the thought is that it will create a narrow view of that place and culture, and stereotypes will be created. People from outside that place or culture will not truly understand if there is only one point of view. This could lead to conflict, exclusion, fear, apathy, etc. (the dangers).
World literature provides many voices and lenses in which to view the world. Representation matters because everyone is different and everyone has a story to be told.
You can kind of relate it to Marvel's Black Panther. Prior to that movie, there were a lot of successful superhero movies that had the theme of good vs. evil. However, Black Panther was led by black actors and gave a backstory of Africa (something we had not seen on screen). Obviously, Black Panther is massively popular, and proves that superheroes do not need to be only white characters (mostly men at that). Black Panther's version of Africa/the homeland is much different than what we have gotten in popular culture. Usually, Africa is associated with disease (HIV), famine, poverty, corruption, dictatorships, civil war, and exploitation of natural resources. Yes, this all happens in Africa, but Black Panther found an empowering and beautiful story to tell a different side. Although Black Panther is fiction as is literature, the human element comes from truth which is at the heart of stories.
*If "a single story" is not what you mean by this, then can you give a bit more information on the question you are trying to answer?