D’varim 4:6-9. In verse 6 it says... "When they hear of all these laws, they will say: Surely a wise and understanding nation is this great nation". Who is it talking about?

In every generation there are gentiles who see the wisdom and depth of the Torah of Israel, attributing it obviously to God, Giver of that Torah (as is explicit there in the following verses). As time passes, mankind matures, and more and more gentiles, like yourself, realize the depth and morality the world will gain from Israel and her Torah, and will accordingly respect, befriend and support them.