Unlike Jay Gatsby, who spins a romantic vision for himself, Nick Carraway sees life in terms of "now." And, he perceives life as it truly is. So, when he says,
"I am one of the few honest people that I have ever known,"
Nick is being objective and realistic, not boastful. For instance, in Chapter Three, Nick narrates that his descriptions of Gatsby's parties have not really absorbed all his attention. He has been working in lower New York and enjoying life in the city.
I began to like New York, the racy, adventurous feel of it at night and the satisfaction that constant flicker of men and women and machines gives to the restless eye.
On the other hand, he confesses to feeling a "haunting loneliness sometimes, and felt it in others." A keen observer, Nick notes that there are many who are solitary or others who are frivolous, waiting for taxis to take them to places of gayety and excitement.
"Full of interior rules that act as brakes on [his] desires," Nick tells the reader that he has felt it necessary to get himself "out of that tangle back home" before he becomes involved with Jordan Baker. Thus, Nick acts as the moral center of Fitzgerald's book as an honest man who is admittedly "inclined to reserve all judgments." As such a person, Nick does seem rare as an honest person when compared to Gatsby, Daisy and Tom Buchanan, Myrtle Wilson and her friends, and all the guests of Gatsby's parties. His statement that he is the most honest person he knows is both candid and satiric, thus lending the narrative validity in its candor as well as insight into the amoral Jazz Age in which Nick and the others are immersed as he describes New York that he likes, but perceives as very lonesome.