I ask because I got sent on a fishing job to steal a flawless diamond. I created four enchanted items, each with +40 Sneak / +40 pickpocket. I went to steal the Flawless diamond... 0%. I should note several other peices of stuff on her had the chance increase to 90%, despite not having any perks in Pickpocket. (I know 90% is the max). What do I have to do...to steal this thing? Ive kinda maxed out my Pickpocket as far as enchantments go!

Quit the job and try again for a lower-valued (and therefore easier to steal) item?

As far as I know, pickpocket is bugged when it comes to enchanted gear. I usually take off my TG gear when I'm going to do some pickpicket, because it actually lowers the pickpocket percentage. And there is another thing, unless you put some perk points on pickpocket and raise pickpocket at least over 30-40, the % won't go up.

Some items may get 90% while some others may get 60,50 or even zero %, it depends on money value mostly (I dunno if weight affects it), a diamond is a valuable gem, so it's logical to be hard (at least to the game) to pickpocket.

Didn't one of the patches address the issue where the deft hands enchantment lowered your chances? I do remember early on that my chances seemed to go down when using enchanted items.

it happened to me recently (on december), on xbox 360 with patch 1.8 . I'm currently playing on PC, but I haven't checked if still happens though.