If you were sexually attracted to children, would you be able to admit it to yourself? If you would not be able to admit it to yourself, then you don’t actually know whether or not you’re sexually attracted to children; maybe you are, maybe you aren’t.
This is a special case of a general principle: the only way to know that you don’t secretly want X, desire X, or value X, is if you would be able to admit to yourself that you do want/desire/value X, in worlds where you really do. If the possibility feels too painful to face, then you can’t rule the possibility out.
In order to know your own wants, desires, or values, you need to be ready to face the possibility that they’re not the wants, desires, or values you thought you had, wished you had, or were told you were supposed to have.

I dunno, man, one galaxy seems kinda small ;)