"Ea este o fată bună."

Translation: She is a good girl.

[-Francessca-]

Santa will be happy

[bluchill]

"lovely" girl would'nt do as well?

[Schattenparker]

I guess that good and lovely are not synonyms in English either: A good flower? A lovely fire fighter? So "good" is more in a moral sense of expected dutiful behaviour, whereas "lovely" is more in a pleasing sense of appealing to your emotions.