How does Justin Trudeau keep getting elected even though he breaks the law all the time?

Trudeau practices a brand of identity politics that is hard to defend against.He spends vast amounts of money to buy the people he needs to vote for him and smears the opposition Conservative party with race and gender charges.

His party members of course invoke Trump whenever they can.

He spent 28 billion $ in a few months leading up to the last election on promises.

He also is irresistible to women and when he gets in front of a camera and puts  on the dramatic bedroom voice all is forgiven even after he has shown by his actions that he is racist,sexist and a criminal.

Right now he is being saved by the 3 other leftist parties who vote in a coalition with him.

Since conservatives want to reign in all the debt he is racking up they can't fight his 'free stuff' government.

Canadians don't want a good president.

"Keep" is probably an over statement.  He has only been elected to parliament four times.  And he has only been "elected" as prime minister twice.

As to his seat in Parliament, with the exception of three elections (including Trudeau's first election) when the Bloc Quebecois was a stronger force in Quebec politics, Papineau has been a reliably Liberal riding.  (Even in those three elections, the Bloc only won the riding once -- in 2006.)  So almost any Liberal should be able to win that seat.

As for being prime minister, most of Trudeau's misconduct arose after he became prime minister in 2015.  It is hard to get a party to dump its leader.  The Liberals managed to get the most seats in 2019, but they lost their majority and saw a significant drop in votes.  The Liberals staying in power had more to do with the weakness of the right (with some fracturing away from the Conservatives) and the weakness of the New Democrats.  

He looks good to women and he legalised weed, so women and young people like him and voted for him. 

He never actually does anything though. Every time he is asked a question, he is always going to look into it in the coming days or something similar. 

Too much weed is bad for people. 

SloJoe Biden is a fairly well documented criminal and pervert and he got elected.  So it's probably not what you know or do, but the money behind you.  

Some of the worse leaders have something that appeals to the voters for some reason.  In the USA,  Trump was a train wreck but he still has many supporters that would do violence to put him back in office. 

He legalized weed. I would vote for anybody who did that.