I guess you can have Assurance with another move to make it stronger. You can have Throat Chop if you want to knock something out in one turn immediately. Maybe in double battles, have something like Stealth Rock on the opponent side and so when something comes in, it will be hurt, making it easier to knock it out with Assurance. Or you can have both and use Throat Chop first to make Assurance stronger. Hope this helped.