"Dishonest" is a little harsh, given the legitimate fear of reprisal you have, but it's entirely possible the *girlfriend* would feel that way. Lesbians don't typically have boyfriends, after all, and straight women don't typically want to end up with a girlfriend (and even bi/pansexual women probably would like to know what they were getting into), so the relationship would be at risk when she found out. There are many, many tragic stories of trans women who lose their beloved when they come out.
(There are lots of happy endings, too - like mine! - but it gets a little harder when she knows that you deliberately didn't reveal this information.)
I want to be clear that I'm not criticizing or judging, though, just discussing the possibly diminishing likelihood of success for the relationship. I have no right to an opinion on how anyone else chooses to live their life or prioritize their own safety.
