满口脏话证明劳资好姑娘
[măn kŏu zàng huà zhèng míng láo zī hăo gū niáng]
Translates as 'A mouth full of profanity proves that she is good.' Here it uses irony. Usually girls don’t speak rudely, thus speaking foully seems to indicate that she does not fit this stereotype and shows herself boldly without any constraints or pretense.