"Discretion and confidentiality are important aspects of my role. As someone who is very loyal to the people and organization I support, these aspects are assumed and carried out at the highest level every day."

The interviewer simply wants to learn more about you as a person! Go ahead and share 3-4 tasks that you are really good at. You might mention: Monitoring and responding to emails, answering phone calls and taking messages, planning and organizing meetings, running errands, maintaining a schedule, giving reminders of birthdays/names/events, selecting gifts for family members, building relationships with your client's clients, telling people no, typing documents, or managing projects.