This session will be intentionally brief and you need to stay focused. As soon as your employee arrives, invite her to sit. Close the door and introduce the human resources representative, if she and the employee have not met. As soon as you sit down, tell the difficult employee the decision has been made to terminate her employment with the organization. You're past the discussion stage.
This isn't a time to engage in idle talk nor is it time to debate the merit or lack of merit in terminating this person's employment. That was all discussed during your constructive confrontations or in the sequence of reprimands, when everything was clearly spelled out. Now it's time to part ways, as professionally as possible, trying to preserve everyone's dignity. The big decision has been made and you are now simply announcing it.
Say you are sorry that she didn't work out in your organization and wish her luck in her next position. Explain that you have her final check. Before turning over the check to her, present the termination paperwork for her to sign. This document will contain guarantees that the terminated employee will not engage in any form of backlash against you or the company, such as lawsuits or slander. Provide information about outplacement assistance, if you're offering it.
Once the paperwork is signed and the check is handed over, conclude the meeting and stand up. Offer your hand to shake, but be prepared to withdraw it gracefully if the person refuses. Escort the person back to her work area to gather her personal possessions.