Can a slave be owned yet unmastered?
No. Not in a society where there is no legal ownership of slaves. Where slavery isn't a legal institution, her owner's mastery of her is the only thing that binds a slave. A slave that is not mastered is not owned in any meaningful way.
Can an unowned slave be owned by her commitments and mastered by her honor and commitment?
No. Acting out of honor and commitment are character traits that Goreans would associate with the free, not with a slave. A slave may act out of devotion, but that devotion is the result of her master's discipline, and again, his mastery over her.
Goreans do make a distinction between the collar and the brand. The collar denoting ownership, and the brand denoting the status of a woman as a slave. In this way, a woman can be a slave, and unowned. I think that it would be difficult to impossible for a woman to be a slave as Goreans think of slaves if she had never been owned. If she had never had slavery impressed upon her by a man, thereby being "branded" as a slave, figuratively speaking.
I ask edana sometimes if she could explain what it is to be a slave to a woman who had never been. She doesn't think she could. There are a number of analogies that can be drawn, but none of them really explain it. edana has been "branded" as a slave, by having slavery impressed upon her, though I haven't gotten around to branding her physically (yet). If something were to happen to me, she would, without doubt, seek out and submit to another owner. Once branded, a slave remains a slave.
The books in a way have fairy tail endings time and time again when it came to the Master / slave relationships. By this I mean in the end they wound up with their perfect match even if it was after a long period of trail and error.
Not all slaves had "fairytail" endings, and yes, Norman showed in his story lines and even said in one place explicitly that a girl might change hands many times before arriving in the collar of the "right" owner. My advice to new slaves, in fact, is always along those lines. Expect to change hands a few times. Expect there to be some reversals and hard-knocks along the way. Thinking that your first collar will be your last is just a recipe for ending up jaded and bitter.
In reading the series four times I failed to see what happens in-between. I failed to see this trial and error, the human emotion, the struggle between a Master and slave when they are bound by collar yet find that they are not a match.
You must have been doing some of that speed reading. You don't remember Ute? Yes, it's true, that here where we live a girl is probably more likely to find herself in the collar of a man who cannot master her than she would be on the fictional Gor, where men were raised around female slaves.
What if either or both feel unfulfilled? In the books a slave would have no choose but to stay, serve begging to be sold, begging to be understood, nurished, Mastered, but what about in real life?
A girl can beg to be sold, understood, nurished, and mastered. The only difference is that here, she can simply choose to run off if she is not kept in bondage.
Another twist to this scenario. What if a woman enters into a "vanilla" marriage and finds herself aching to serve, needing to be mastered? What are her true options? Would this scenario be much different from a collared slave feeling unfulfilled and unmastered?
It happens. Often. She can stay and remain unfulfilled for the sake of commitments that she has made. She can beg her spouse to become her master (really, really really tough to do, especially if they've been married a while. Not impossible, but really hard). She can leave and seek a master. None of those choices are easy. Life is tough sometimes.
Another spin on this scenario, is the woman not a slave to her marital vows, to her commitment to her husband and her family?
No. You can twist logic until it cries uncle if it makes you feel better, but women aren't slaves to their wedding vows any more than saying the pledge of allegence makes you a slave to the United States. Honoring a commitment is honoring a commitment. It's not slavery in any sense of the word.
Take care of yourself