Well "Art not without ambition; but without the illness should attend it." means he has ambition, but does not have what it takes to use it to gain something.
"Though wouldst be great" means he wants to be great, but "What thou wouldst highly, that wouldst though holily; wouldst not play false, and yet wouldst wrongly win" means he wants to do things in a good or holy way, he doesn't want to cheat in life or play unfairly, but he does want something that shouldn't be his.
She is basically calling him out, saying he wants to be king but doesn't have what it takes to make it happen.
So I believe the answers would be He lacks courage, and He has moral scruples.
For future reference.
