Will the *real* real Diana Prince stand up?
To remind you, the setup is this: Wonder Woman has delivered Steve Trevor to the military hospital but wants to remain close to him. She finds a nurse who is weeping over being parted from her fiance who has gone off to South America because she cannot afford to join him. Wondy offers to finance her trip if the woman named Diana Prince will trade places with her since, not only do they have the same name but they are also conveniently near identical to look at. The somewhat naive nurse then agrees to hand over all her identity papers to this strange foreign woman in exchange for sufficient money to take her far away, and never considers that this is not the most appropriate thing to do when your country is at war, and meanwhile nobody in the hospital notices the substitution, or even that one of the staff has acquired muscles and a foreign accent.
So what is to become of the real Diana Prince?
In Sensation Comics #9 (1942) we find her returned to the city now married and with a small child. Her husband is trying to sell a new kind of artillery shell he has invented but is so far unable to interest anyone and so real Diana Prince (now Diana White) contacts WW Diana Prince to say she wants her job back. After all sorts of fun with enemy spies, WW gets the husband's invention taken up by the military, and so Real Diana Prince can go back to being a full time mother and getting her hair restyled so they don't look so similar.
In Wonder Woman #167 (1967) WW receives a letter from Real Diana Prince once again saying she wants her job back, although this time it is because her fiance (they didn't get married yet in this version) is lost in the mountains and she doesn't expect to see him again. Either this is subtle blackmail (come find my fiance or I'll expose you) or disguised cry for help (if I tell you about my problem maybe you'll come fix it), because taken straight it doesn't make a lot of sense. Wonder Woman of course rushes off to help her. It transpires that Bill, the fiance has been captured by a lost tribe of Mayans, or possibly incans (it's hard to tell as they are a bit generic) who compell WW to undergo several trials in order to save him. Luckily he has found a wealth of rare minerals in the sacred mountain so once again real Diana Prince can look forward to the good life exploiting native lands and doesn't need her job back.
In Wonder Woman #237 (1977) Real Diana Prince has been stalking her double for several issues, having forgotten that they traded places. She has spent a year in South America and returned to find someone else pretending to be her. The fiance is not mentioned. Her double reveals herself to be Wonder Woman in disguise and explains how she took her identity, finishing with the reason that she had forgotten was because WW used her magic lasso to compel her to forget in order to protect her secret identity. Having explained it all and handily done a recap of her origin for the new reader, WW lassos her again and makes her forget once more, leaving her to wander away while she rushes off to battle a monster.
Of the three this is easily the least satisfying, leaving Real Diana Prince as a thinly drawn cypher on which to hang a recap WW's origin story. We never find out what she did in South America, why she returned, or what became of her fiance, and at the end she is just left to wander off. The second version is also really just an excuse to get WW into an exotic location; otherwise the presence of real Diana Prince has little relevence. In fact it is only in the original sequel that Real Diana Prince becomes anything like a rounded individual with a life that has moved on since her first appearance. And that is achieved in half the number of pages of the third version.
Of course I am now fully expecting to find yet another version of this story from the 1950's, but such is life.