She's not dumb, but I think her greatest asset is her heart, not her brains.

The two main moments that stand out to me are:

When she convinces her stepmother to allow her to attend the ball (when they make the deal that she can go if she finishes all her chores), after her stepmother and stepsisters try to tell her that she can't go. And she points out exactly what the invitation says and that they pretty much need to allow her to go! And also...

When she turns out to have kept the other glass slipper, and it's a good thing she did! When I was a kid, that was the most satisfying part of the movie for me.

So I guess both of those are to do with her common sense. She's not a character I particularly think of as being especially intelligent or anything, but I do think she is sensible.

All. Especially wisdom.