Feeling confident on the day of your viva isn’t a magic shield against difficult questions. It doesn’t mean that you won’t or can’t feel nervous about the prospect of meeting your examiners.
Feeling confident for your viva means you’re as certain as you can be you’ve done as much as you can to get ready. You’re certain your work has value. You’re certain that you are capable. And you feel certain that whatever questions your examiners ask you will be able to engage with them and respond to them.
Viva day confidence is built up through work and reflection – and thankfully you have plenty of opportunities over the course of your PhD and in your viva preparation to build up your confidence.
Remember the work you’ve done. Remember what it means. Remember what a difference your learning and research and effort have made to you. Reflect on the work and all the impacts and you have the firm foundations for feeling confident on your viva day.