if she performs excellently, $100 can treat as bonus. But have to remind you don't always reward maid with money, instead can buy a small gift. BTW, just get the $100 dollars back from salary (if you like, you can use it to her food/gift). Let her know that you're so easy to give money. And let her know you mind. Nothing to strugle. It's no big deal even if you get the money back now. Just very normal.