Note that in the USA there are typically three kinds of assistants: (1) they're an established business and you simply pay their quoted rates, in which case they don't net all that you pay them due to their overhead and IRS obligations, (2) they're classified as a "household employee" and the IRS wants both of you to cover extras like Social Security and Medicare, in which case their paycheck has deductions and you owe taxes to the IRS, or (3) you give them under-the-counter cash payments to avoid paying taxes, but that's illegal.