“Eventually, it seems like there must be a point where you say ‘no I wont do that’ to accomplish a belief. So if I as a player want my character to remain true to what I had created them like (in one way, not in every way) I could simply not ever write a belief about this characterization.”
I’m not sure what you mean by this statement. There is nothing is Burning Wheel that compels a player to take actions that the character would not do. The GM may dangle a really hard choice in front of you to tempt you to betray one part of your character to fulfill a belief. Whether you stay true to the original character concept and ride out the consequences, decide that this forces a changes of heart and rewrite your beliefs, or whether you cave in a moment of weakness and redouble your commitment to the challenged belief, that is all great stuff. So putting up a Belief doesn’t come with an expectation of that Belief being changed though it certainly can.