I thought my ex knew, but turns out she just thought I was gay...despite the fact I never flirted with men, and I only had sex with her. Apparently having an appreciation for clothes and acting femme just made her immediately think "gay". Which is insane because if that is what she thought, then why marry me lol? I had to come out to her as trans, and then come out to her as trans again because apparently the first time didn't "stick", she thought I wanted to be a drag queen the first time...
I suppose my point in all of that is, many people will think something is up and go somewhere not quite right with their thoughts. Many people also don't understand being TG isn't the same thing as crossdressing, drag, etc. So be weary of people who act knowing but, are thinking something quite different from what you are.