In Joseph Conrad's Heart of Darkness, Marlow is the principal narrator and he satisfies his obsession with deepest Africa by journeying into its depths and returning to tell his story, barely surviving in the process. Marlow's last words refer to his recognition that different people have different realities and mankind can only hope to exist if there is a mutual acceptance of each other's individual and collective needs and a co-operation that requires a deep understanding and a universal perspective. This is why he feels justified in lying to Kurtz's fiance. The pain he feels is the crushing knowledge of mankind's desperation and darkness, his selfishness and self-absorption and the possibility that life is nothing more than "that mysterious arrangement of merciless logic for a futile purpose." He resents any sense of normality as if people are merely "intruders whose knowledge of life was to me an irritating pretense, because I felt so sure they could not possibly know the things I knew." Marlow is somewhat overwhelmed by the responsibility of talking to Kurtz's fiance as if "the heavens would fall upon my head," and his words reveal how he struggles and justifies his actions. He knows that what he tells her may seem like a "trifle" to the uninformed but that is because they have no concept of "the horror."
Marlow is conflicted by his fascination with, and disgust for, Kurtz although Marlow does apparently remain loyal to him, even though this representative of the "International Society for the Suppression of Savage Customs" as he initially sets out to be, is a savage himself. Marlow maintains that Kurtz is a "remarkable man" because he is able to achieve real self-realization and a stark honesty that is rare but also debilitating. Marlow hardly knows Kurtz but is so astounded by his recognition of "the horror" and whatever that might represent to any individual, that Marlow finds it necessary to create a reality for Kurtz's fiance which would defy Kurtz's beliefs (or sense of "justice") but which Marlow must do if he is to show real understanding of Kurtz's purpose. Kurtz's fiance's reality is so far removed from Kurtz's own that Marlow knows that she can never comprehend it so he must maintain the illusion in order to preserve the image, for her benefit.
This makes the end so significant because, through Marlow, the reader is exposed to and must face the fact that everyone has a different perception of horror or goodness, right and wrong, civilized and savage, and it is only complete self-awareness that leads to absolute understanding and honesty. By safeguarding Kurtz's reputation, Marlow must admit his own shortcomings, allow Kurtz's fiance to retain her high expectations of Kurtz the man, rather than the savage and accept the unfathomable "horror" whilst allowing civilization's basic view of the savagery in which Marlow found Kurtz wholeheartedly immersed. Civilization is not ready for a man like Kurtz and Marlow is barely ready to accept that there are similarities between himself and Kurtz that suggest that he may have found himself similarly affected had his circumstances been different. The reader must measure Marlow's integrity for himself or herself.