An out-of-true wheel and a bent wheel are two very different things. You can true a wheel with a spoke wrench, but a bent wheel has to be bent back. Luckily, there's a way to get them straight, even if it's only straight enough to get you home.
Your local bike shop probably knows this hack well, even if they'd only do it while your back is turned. But there's actually a bit of science to it. When there's enough lateral force to put a serious bend in a rim, the wheel's structure naturally forces two other bends to appear on either side of it. By laying the wheel on the ground with the big bend facing the ground and turned toward you, you can step on the two minor bends, pull up on the opposite end of the wheel, and cantilever your weight against the main bend to get the wheel back in round.
Start with a light touch until you feel the wheel bending under your weight. It'll feel odd at first, but eventually you'll get a sense for how hard to push. You'll need to fine tune it with a spoke wrench once you're done, especially because the spokes may have stretched.
Keep in mind, this will only work for alloy rims, and it may not be a permanent fix. You might end up with spoke tension inconsistencies that could weaken the rim. But this will get you home and save your ride.