Diligently is definitely more accurate. Hard can mean too many different things according to context. It's confusing for learners.
네. 그녀는 예쁜데 게을러요!
Isn't 열심히 diligently or someone informed me wrong?
I was taught in my Korean class that is was "diligently" so... lol It should be accepted.
It can be. Hard works fine too though.
I supose it means hard. Diligently is propabely 부지런히... Am I right?