I suppose one of the main qualities to having a "good heart" would be how willing they are to help their fellow man or woman. Usually, someone who offers a helping hand even if they don't really want to can be said to being "good natured" because they are taking their own time to help someone else selflessly.
It's a human tendency to judge anything. Naturally we avoid things that cause us pain and enjoy things that cause us pleasure. With regards to others, it differs from person to person. Some people will immediately vocalize their judgements on strangers, not knowing them properly. Whereas others will hold their judgements until they know the person better.
I have often judged people prematurely only to discover that they are the nicest people I have ever met. Hope this helps!