If you wanna die fast, then try cutting an artery instead, the ulnar artery is the most accessible of them all i must say. It's located below your elbows, so cutting through any extension of your arms would do the trick. You'd lose a shit ton of fluid, your brain would lose oxygen and die in seconds, not sure if it would be painless though.
There is no way of numbing the pain of cutting veins or arteries, pain is just your nerves alerting your brain that something is not right at that region.
Hope you learned something with that info and hope it made you realize that suicide is not an option because your family cares about you :) Have a good one.