In his campaign, now, he is absolutely espousing conservative values. In his personal life he doesn't drink or smoke and his children seem to be intelligent, productive and well mannered.
The knock against him is that he's "lying" about what he's espousing now. That goes against his character. In the business world and especially in real estate transactions involving millions or billions of dollars lying will get you sued or in jail. If everything's not air tight legal you're screwed. It's out of character for him to lie.
I don't know whether he's lying or not. But his record suggests that he's not being perfectly frank.
The knock against him is that he is an opportunist demagogue who is simply playing to whatever generates the most applause at the moment. He will say one thing today. Tomorrow, in front of another audience, he will say something else. And he will "mean it" both times.
I think Trump was completely sincere all those years when he was a conventional Manhattan liberal celebrity, aggressively pro-choice, celebrating planned parenthood, supporting Obamacare, and contributing to Hillary, Chuckie, Nancy, et.al. I think he is completely sincere now, playing to Republican crowds, when he adopts to opposite positions. I think he was completely sincere when he approved of the U.S. war in Iraq, and completely sincere when he went Code Pink a couple of weeks ago.
"Sincerity," however, does not mean the same thing to Trump as it does to most of us. Donald does not have principles. He has impulses, and angles to play, and deals to make. Will he sacrifice political popularity to nominate and support conservative Supreme Court nominees, or reform entitlements, or repeal Obamacare? What in his record makes you think there is any principle that he will not abandon as soon as it is convenient to do so?