One of my absolute all-time favorite scenes in Star Wars anything is the bridge scene on Endor. Luke, on the verge of having to face the full consequences of his birth, doesn't ask Leia for assurances. He doesn't start out by making a heroic statement.

He asks about Leia's mother--her real mother.

Now, I find this slightly interesting, just a bit. What I think of when I see that scene is that he's trying to put together as much of his familial consciousness as possible. He has recognized for himself and for Leia their rather alarming connection to Vader. He knows how important his tie to Leia as her brother is.

The missing link is what part of Padme Luke and Leia have in themselves. This is particularly puzzling since we know that Padme actually made physical contact with Luke before dying, but we have no indication that Leia had the same.

He can be looking at Leia and wondering if she looks like their mother, if she got her strength from Anakin or Padme. If he recognizes that it might be from Anakin, he also has to realize that she has the same ability to become like Vader that he does. I wonder if he remembered the cave at that moment.

On the other hand, I have been wondering about Leia of late and her knowledge of her origins. Obviously, she knew of her adoption or at least that she's had more than one mother. It has been suggested to me that the 'real mother' she spoke of in that scene is Breha, but that doesn't really make sense to me.

It's never been explained in canon why Bail and Breha "always talked about adopting a baby girl." I, of course, have my theories, but that's fanon, nothing more. I think if they had talked about it, there were others on Alderaan who knew that they had difficulty having a child.

Was her adoption something known outside of the Organa household or was it something that people might have suspected but never stated?

Did Leia know that she was adopted because of Bail telling her or did she have an innate knowledge of her not quite belonging there at times?