GOP will never promote Trump. That's what I think.

The Republican establishment doesn't like any "outsiders", not just Trump, but a "brokered convention" means only that none of the candidates gain enough delegates in the primary elections to win the nomination at the convention on the first vote. Current Republican rules require a simple majority. With over a dozen candidates currently still running before they later run out of money and have to drop out, and no primary elections until next year, it's a bit early to speculate about a "brokered convention". It isn't something that can be arranged for without regard to upcoming primary election of delegates.

Terrible idea if Republicans tried something like that. If the guy wins the election primaries, they need to respect that process.