Quote Originally Posted by powertripper View Post
How do I judge her opinion/concerns about some of my commands when she always does as I say without question?
Teach her - forcefully - that giving you accurate information is part of the service you require. If you tell her what to do, of course she must obey without argument: but if you ask her what she wants to do, and all she can say is "Whatever you wish, Master," she's holding out on you and disobeying.

If she has trouble opening up, I suggest devoting some time to an interrogation scene where you explore her feelings the hard way, with heavy punishment for anything less than complete and honest answers.