Are you the new person drawn toward me?
To begin with, take warning, I am surely far different from what you suppose;
Do you suppose you will find in me your ideal?
Do you think it so easy to have me become your lover?
Do you think the friendship of me would be unalloy'd satisfaction?
Do you think I am trusty and faithful?
Do you see no further than this facade, this smooth and tolerant manner of me?
Do you suppose yourself advancing on real ground toward a real heroic man?
Have you no thought, O dreamer, that it may be all maya, illusion?
"I am surely far different from what you suppose" is the line that best sums this poem up. This deals with expectations others have of others, and how reality is almost never in line with perception, particularly with regards to people. Friendship and love are not the panaceas we so often hope they will be. Things are not always as they seem. "Have you no thought, O dreamer, that it may be all maya, illusion?"
The poem comes across as almost hostile in its warning, but I think it's out of a desire for the one approaching, the person drawn towards, to make sure that it is not out of selfish reasons. Whitman is not saying that he is not trustworthy of faithful, but he asks these questions to make the one approaching question one's self.