If the damage is from a catastrophic blow to the wheel from the bumper of a car, it is almost certain the issue is a bent rim that can not be properly fixed by truing/spoke tension. It might be possible to get it rideable (or more ridable) by bending it back as shown in the video above with the person standing on the wheel laid across two boards, but this is generally a 'last resort' repair and will require very unbalanced spoke tension to get it close to perfectly straight, which results in a singificantly less-strong wheel.

If you can get a new rim of the same model (or just one with very similar dimensions) then you can likely re-use the spokes. A less-experienced person can do the repair by taping the new rim to the old rim and moving the spokes over one at a time, but this consumes much more time than relacing, although relacing will require more time to unlace the spokes one by one - if you are using new spokes you can just cut the old ones out and it takes 1/10 the time.