How would you like to simplify it? That's about as simple as you can get, but some folks get nausea and headaches when they see a radical in a denominator.
\(\displaystyle \sqrt{\frac{2}{3}} = \frac{\sqrt{2}}{\sqrt{3}} = \frac{\sqrt{2}}{\sqrt{3}}\cdot \frac{\sqrt{3}}{\sqrt{3}} = \frac{\sqrt{2}\cdot \sqrt{3}}{\sqrt{2}\cdot \sqrt{3}} = \frac{\sqrt{2\cdot 3}}{\sqrt{3\cdot 3}}\)
Can you finish?
I still think this final result is no more simplified than where we started, but I tend to be in a minority on this discussion.