I don’t think Bill had any particular charm either....it was because the press loved Bill and they covered for him. Everything bad about Bubba didn’t come out until the Clintons were no longer useful to the gungrabbing babykillers.
People who agree with politicians are already half-way to being charmed by them. If politicians don't manage to alienate or annoy or offend you, they get that much closer. It doesn't take much on a politician's part to reach the goal.
If you don't agree with the politician you aren't going to be charmed by seeing them on television or reading about them. In actual encounters, some people are won over in spite of themselves. The politician has to be confident, not make any obvious mistakes, and find some way to draw the other person in. It's a skill some politicos have and others don't.
Bill demonstrated that his true desire was the access to myriad females that the offices of state attorney general, governor of Arkansas, and then POTUS afforded him.
It was Hillary's ambition for him to be president so that she could wield the power behind the throne.
An interesting 'take' on the situation...