A Smile like the Cheshire Cat

     It's often said that a smile is worth a thousand words. In my 16 years of life experience, I've found this to be the case a majority of the time. To me, they are the gateway to a person's heart, and can hint at someone's thoughts and feelings in a matter of moments. For example, a forced smile indicates duress or a degree of unease; A genuine smile paints a picture of comfort and joy; A smile laced with malice serves as a warning to others.
     I like to think that I'm decent at interpreting smiles and the motives behind them, but Jay Gatsby's smile just confuses me. When the narrator Nick first meets him, he is described as having a "rare...irresistible" smile as if he sees only the best in you. It's a genuine smile that makes it seem as though he cares.
     However, the smile abruptly vanishes, and Nick's image of Gatsby is shifted from an ideal, compassionate young man to a "roughneck" who tries too hard to impress others by using formal speech bordering "absurd[ity]".
      So, which is it? Is Gatsby truly a kind-hearted person, or is he just a small man looking to impress others? At this point in the novel, a few chapters in, I'm leaning towards the latter. He learns from an early age that "people lik[e] him" when he smiles, and, since he smiles a lot, he might just be groveling for attention.
     I really hope I'm wrong, not only because it'd make me feel better knowing that not all characters in books are complex but terrible people (see The Bluest Eye for examples), but also because it would be a pity if someone as handsome as Leonardo DiCaprio played such a cold person.

Leo is mocking me with the uncertainty of Gatsby's smile