I think you can.
It is her problem if she does not report her income, not your problem. However, you are required to withhold social security for her on behalf of IRS. You also need to pay social security for her as well. In other words, half and half.
Pay social security before you claim expenses against your spending account. Otherwise, you will be in trouble.
Pay social security before you claim expenses against your spending account. Otherwise, you will be in trouble.