A good wife is one that can make the most of a marriage. I don't think there's one cookie-cutter word like "trustworthy or loyal or compassionate" that can begin to define a good wife.
The key to a happy marriage is fun.
A good wife knows how to have fun WITH her husband and her family. If you can't have fun with your family, then the family will not communicate as well, they will not spend as much time together, they will not want to be with each other as much. Yes, there will be bad times, but if a wife (or a husband) can make the good time more fun, then the family will remember the good times more than the bad times.
I think that's why so many people end up in therapy - they only have memories of the bad times, the disappointments, the let-downs, the tragedies - not the good times.
If I had it to do all over again, I would stress less about paying bills and getting to work on time - and more about how I can make today the best day ever for my family. I think a good wife would do the same.