I think doubt just means you have a functioning brain that recognizes the dangers and social consequences of being trans. So I tell myself and congratulate myself on my self awareness, anyway.

I would have to agree with you about that. A big part of the doubt for me is that I really only started questioning after reading about gender online, rather than online material simply confirming feelings I already had. But I also know that if I was truly cis, I probably would not still be questioning 8 months after first reading said material.