I wrote a post awhile back about interracial dating. I have zip zero problems with it except in THESE cases. I was talking about white men at the time and said something to the effect of if you're scared of her brothers, uncles, father, grandfather, cousins, etc. and immediately are uncomfortable at just the sight of them (and not in the usual "meet the parents/family" way) they'll feel that vibe. I am not a black woman who cringes when I see a white woman and a black man dating/married, etc. But I can INSTANTLY feel the vibe of a white woman who is uncomfortable around black women. It's a very distinct feel. About the only way I can describe it is seeing a police car/van drive behind me. You're just very aware of them. Something is "off."
But in all fairness, I dated a couple white guys who had LEGITIMATE black friends and it was immediately obvious, specifically the one who grew up in a predominantly black neighborhood. He didn't do the weirdo shit and start trying to act "blackish," but he easily just blended in. It's so hard to describe, but I feel like quite a few black folks (black women especially) can just "tell."