Why is, "Sunteți o fata dișteaptă," incorrect?
It's correct (apart from the typo "dişteaptă"). If it was rejected it was probably just because you're less likely to use the formal you (sunteţi) when addressing a girl.
Gotcha. I suppose it could happen though. Haha
Why "inteligente" is not accepted? Instead of dişteaptă..
how come you have the same typo as the previous one? copied from there?