Given the nature of his businesses, the only way he could possibly "leave his companies in total" would be to sell to someone completely unrelated to him or his family.

Turning the business over to his kids won't do it.  Putting it into some sort of trust won't do it.

Anyone that thinks it will seems to be ignoring the fact that if a foreign dignitary stays at a Trump hotel because staying someplace else could be seen as disrespectful presents a conflict (and once he's in office it actually puts him in violation of the Constitution).  That doesn't count things like bringing his kids to meetings with foreign dignitaries (the fact that his daughter was flogging her line of jewelry during the meeting wasn't exactly kosher).  Or conversations with foreign heads of state that could potentially influence his business (it was pure coincidence that his Argentinean project got approved a couple of days after his telephone conversation with the President of that country - end sarcasm)