Empirical studies show that sentiment, implied volatility slope and risk-neutral skewness all predict future stock returns. High sentiment and steeper implied volatility curve typically predict negative future returns. However, evidence of return predictability from risk-neutral skewness are mixed. This paper proposes a theoretical model that explains and reconciles these empirical findings. We show that up to a sentiment threshold, implied volatility slope becomes steeper when sentiment is higher. The threshold is large enough to contain most empirical situations. The relationship between risk-neutral skewness and sentiment (or implied volatility slope) can be either positive or negative depending on market conditions. Our model helps explain the difference between implied volatility curves of index options and stock options. It generates implied volatility curves that are consistent to empirical data.