Rule: Avoid double negatives. Hardly and scarcely, though they don’t begin with an n, are negative.
Note: Sometimes a double negative can be used to make a point about an extreme positive. This technique is called litotes. For example, Michael Jordan wasn't the worst basketball player everimplies (correctly) that he was truly extraordinary.
Examples:
Wrong: He couldn’t hardly believe his good luck.
Better: He could hardly believe his good luck.
Also better: He couldn’t believe his good luck.
Wrong: Nia didn't want none of the boring shoes.
Better: Nia didn't want any of the boring shoes.
Also better: Nia wanted only the exciting shoes.
Practice eliminating double negatives:
Resources for further explanation of double negatives:
Oxford's Dictionary's What is a Double Negative?
Literary Device's Litotes