Are you talking about Attitude? I thought that might have had something to do with it, because my rogue thief had no problem sealing anything from the vendors in the grove, and he had an Attitude of 9. My other characters only had attitudes of 1, and couldn't lift anything from them. But then I found that once I got them to level 3, it got easier even though the Attitude didn't change.
Some tips for fellow thieves:
1. If your player character doesn't have good dex and stealth, then use Astarion as your thief. Especially if you had him select the thief path.
2. If you're having a problem lifting items, then steal the coins and buy the item. Coins are easier to steal than items. And you can always steal the coins back after buying what you want.
3. But coins also have weight to them, and the more you try to steal the harder it will be to pass the slight of hand check. Especially if it's over something like 2000 gold. But don't despair! Instead pickpocket, and Split the gold in half while it's still on the shopkeeper. You will see the required roll for stealing the smaller pile of gold drop. Steal half, then the other half.
