Can a spellthief steal multiple spells per sneak attack? like if you have 3d6 sneak attack can you give up the 3d6 to steal 3 spells or can you just give up 1d6 and only steal 1 spell.
No. It says you can give up 1d6 to get one spell, that's all. But it seems like you can combine different abilities in one sneak attack, e.g. give up 1 die of damage to steal a spell and a second die to steal a spell effect.