Capable
From Wiktionary:
Able and efficient; having the ability needed for a specific task…
Sound like someone you know?
If your viva is coming up, how did you get to this point? How else could you have got here apart from being a capable researcher in your field?
You might be feeling nervous right now, you might be looking for confidence, but you’re definitely capable.
You have the skills, now take action to boost your confidence. What’s your first step?