If your helper breaks expensive stuff is it fair to deduct their salary? The helper broke a $2000 vase which I said to be careful

Oh my. If this is her first time, just talk to her. In the first place, breaking the vase was not intentional. Consider the salary that she earns and the family that she supports if you deduct her salary for that vase. If and when this incident happens the second time around, maybe then you can do a deduction.