Ela é a garota mais bonita da classe. É uma pena que seja tão grosseira.

[theogarver]

English Translation

She’s the prettiest girl in class. It’s a shame she’s so gross.

I think that the sentence is saying that she is rude, but the translation does not reflect this well.

[sjfree]

Yes, rude or obnoxious would be a better translation of grosseira. Substituting rude for gross, I think the translation is alright.