Character Analysis
We're going to level with you, folks: we really have no idea who this gal is. The facts are as follows: she was the daughter of Berlin's chief of police, she grew up to be a famous theater actress, she married Campbell, she entertained German troops during the war, and she died (most likely) after being captured by Russians.
We also know she was Mona Lisa beautiful, and that Campbell really, really, really liked having sex with her. No, really: he even wrote a book about it. We know more about her body than we know about her. Our one insight into her personality is this observation by Campbell:
I would have lost nothing by telling her. My telling her wouldn't have made her love me less. My telling her wouldn't have put me in any danger. It would simply have made my heavenly Helga's world, which was already something to make The Book of Revelation seem pedestrian. (10.2)
Here's the problem: beyond saying that Helga liked things shiny and fun, these lines say more about Campbell—and his need to cover up his guilt over hiding that he's a spy from his wife—than they reveal about Helga.
We know that she was famous and sparkly and light. Without her, Campbell's world was dark, just as in a sappy love song. That's precious. And a little gag-a-rrific.
Perhaps we shouldn't be so surprised that when Resi pretends to be Helga fifteen years later, Campbell swallows it hook, line, and sinker. We mean, sure, he probably wanted to have his past back. But you'd think, after documenting so much sex with his wife, that he's realize he was having sex with someone else this time around. Right?