On Ted Cruz: In January 2016, Trump said, "I don't think Ted Cruz has a great chance, to be honest with you. … He's a nasty guy. Nobody likes him. Nobody in Congress likes him. Nobody likes him anywhere once they get to know him." In December 2015, "I really do. I like Ted Cruz a lot."
On Iowans: In January 2016, Trump said, "I love Iowa. We've done really well here." In November 2015, "How stupid are the people of Iowa?"
On Hillary Clinton: In July 2015, Trump said, "Hillary Clinton was the worst secretary of state in the history of the United States." In March 2012, "Hillary Clinton, I think, is a terrific woman. I mean, I'm a little biased, because I've known her for years. … I think she really works hard, and I think she does a good job. And I like her."
On Megyn Kelly: In December 2011, asked by Fox News host Megyn Kelly if he'd be a better moderator than her, Trump responded, "No, I could never beat you. That wouldn't even be close. There would be no contest. You have done a great job, by the way. I mean it." In January 2016, Trump said, "I have zero respect for Megyn Kelly. I don't think she's really good at what she does. I think she's highly overrated."
That doesn’t even get into his flip flops (most of them recent) on immigration, abortion, and a bevy of other issues.