I think Tiana and Rapunzel are both smarter than Belle, but Mulan is the smartest in my opinion.

and Tiana

Re-watching Snow White made me realize that she's actually quite intelligent!

^ I think she's intelligent too! (Although I still think Tia is smarter.)

Mmmm. Belle is an intellectual ( in a cut scene she is reading Shakespeare's Romeo and Juliet to Adam), while Tiana is a pragmatist. Being intellectual and a pragmatist are not the same things as intelligence. And while I can respect Tiana for being practical, I find her rather narrow-minded most of the time. Mulan is smarter, because she does a lot of abstract thinking, and invents new ideas to test to solve her problems. Mulan mopes only twice: once, after her father tells her that she "should know her place," and the second time after she is left on the mountain in disgrace. Both Belle and Tiana continue to mope when things fall through for them, and they really don't do much after their discouragement... at least, not until other characters prompt them to do more.

I'd say that Tiana, Rapunzel, Jasmine, Snow and possibly Cinderella are smarter than Belle, but I think that Mulan is the smartest.

Aurora is the smartest for me.