One of the most striking aspects of Gatsby's conversation in Chapter five is the secretive nature of much of it. When he talks to Nick about getting him a job or putting him in a good position to make more money (having seen the rather humble circumstances Nick is living in) he can't tell him anything about it, avoiding questions and saying it is a rather confidential thing.
He is magnanimous and withdrawn at the same time, totally afraid of what will happen when he meets with Daisy again. He extends himself to Nick and then completely withdraws once he thinks that Daisy isn't going to show up.
So we learn that he is involved in some shady business that he can't tell anyone about up front, and then once Daisy shows up, we see that he is buoyed by what he sees as the possibility of their future romance.
At the beginning of the chapter, when Nick tells Gatsby that Jordan asked him to invite Daisy and Gatsby to tea, Gatsby's words are awkward. Jay is embarrassed and he tries to make an offer to Nick as a payment for the favor of inviting Daisy to his house. This shows that Gatsby is not the suave, sophisticated man that he has been seen as so far in the story. This shows the truer man. His attempt to repay Nick also shows that, in Gatsby's world, everything has a price. No favors are done without something gained in return. That illuminates the class difference between Gatsby and Daisy (Nick is part of Daisy's world, not Jay's). When Daisy comes over, Jay is extremely nervous and again shows his lack of sophistication. When Daisy, Jay, and Nick go to Gatsby's house, Gatsby's dialogue takes on the bantering style of a little child showing off his collections of wonderful toys. He becomes almost a braggart in his attempt to show Daisy that he has made it in the world and that he is wealthy enough to deserve her and to treat her in the style to which she is accumstomed. Jay's entire demeanor as he shows Daisy through his house is one of wonder and eagerness.