“In his books, Mr. Trump says he favors saying and doing anything to get an advantage in a business deal. Would that work for him as President?”
I think you answered your own questions. To put it more simply, Mr. Trump thinks all is fair in love and war and is not above lying to get what he wants. We already have a president that does that. How has that worked out for us so far?
No, I do not think someone who is a skilled liar is someone who I would want for POTUS.
Can you document that he has ever included dishonesty in that?