Basics first.
The rms rating(power rating, output) of the amp should be lower than sub or else you're gonna blow your sub!
You need to check the actual rms power handling of your sub; read the small prints on the corners of the sub's box/package, not the big letter 2000WATTS. If the power ratings of the amp and sub are equal, then you'll have to lower the gain of the amp.
There are two ways of driving your sub.

I guess your sub is DVC(dual voice coil), so you can hook up 2 amps of max 500 to 750 watts each and adjust gain. Keeps the gains low if the amps' ratings are high to prevent damage to the subs and for better sound quality. There will be 2 separate connector terminals to connect each amp.Another way is to use a monobloc amp. I wouldn't recommend this as mono amps are expensive and you need a good installer to install and tune the whole setup properly. Plus you can always replace an amp if one of the amps goes kaput.
Google and research well before you buy any car audio equipment and find a good installer.
Cheers,
GK