The title 'Heart of Darkness' might refer to the exploration of the hidden, darker aspects of human nature and society that the story delves into.
It could be because the novel focuses on uncovering the profound and often disturbing mysteries and evils at the core of human existence, which is symbolized by the 'heart of darkness'. Maybe it's also a metaphor for the unknown and terrifying aspects of the world that the characters encounter.
The title 'Heart of Darkness' was chosen to evoke a sense of mystery and danger. It suggests that within the narrative, there are deep, concealed truths and moral ambiguities that the characters must confront. It might also allude to the hidden evil or corruption that lies within the human soul, which is the central theme of the story.