You have to disarm people in an everyday situation?
Many arts have modified themselves to doing modern day disarms.. (i.e. knife, gun type disarms). A large percentage of places don't do it right, and the few that do train under the understanding that it is extremely rare for you to use any disarms (most of the time you can merely comply with a weaponholder) but that you are going off the assumption that you are indeed hurt or are going to be hurt and you are merely trying to mitigate the damage done to you.
Locks (jointlocks) are taught in nearly every Martial Art, some spend more time on it than others.
Most blended and soft style arts focus heavily on it.
Jujitsu, Judo, Hapkido, Aikido, Sambo, are all heavily joint lock oriented. There are tons of others, it all depends on the school really.
Krav Maga, Kali/Arnis/Escrima/Filipino Martial Arts, Jujitsu, Defendo, Progressive Fighting System, RealContact Stickfighting are just some of the few arts that heavily teach disarms. Essentially the schools that are good at actual disarms tend to be from these systems, especially the FMA type schools.
Truthfully most locks and disarms aren't for an everyday situation, they are worst case scenario. If I have to slap a joint lock on someone I am not looking for compliance or for them to tap, I am looking to take a joint out because it was what was available to me.
Honestly, there is no BEST Martial Art, especially for something as broad as joint locks and disarms. What you can do is try to find a school that trains in these, and most importantly trains them in an alive manner...
Meaning at some point they do hard sparring with two people trying to win.. i.e. guy attempting to stab, is actually attempting to stab, etc.
Person getting put in the armbar is actively trying to not get put in the armbar.
That is how you can develop real understanding and applicable skill.
There are crappy Krav Maga schools and good Tae Kwon Do schools.
It isn't so much about the name of the style of Martial Art, as it is the school, the instructor, and your own individual ability.
20+years Martial Arts