Like petic. I play with the sentences. I try alternatives that seem possible but are different from the ones previously marked correct. Sometimes I am right. Sometimes I am wrong. Both ways, I am learning more than by just repeating the phrases that I know are right.
I forget who said it first, but "Anyone who has never made a mistake has never made anything", so don't worry about it Have fun.
what duo fails to mention is that 'déjà' means 'again' only in questions (like 'où est-ce que nous allons déjà?' "where are we going again?"). as if you wanted someone to repeat the answer.
"she exists again" would be "elle existe encore". or, to make sure nobody confuses it with "she still exists", just say "elle existe encore une fois"
In addition to the excellent example given by Slovenec, I will add one that could deal with an actual person. ______Friend 1: "You know what I want in a girlfriend? Beauty, intelligence, great cooking skills, a forgiving attitude towards all my flaws, and a deep devotion to Doctor Who." Friend 2: "Right, like you'll ever meet someone like that. Maybe one day science will advance to a point that you can create a woman like that, but until then--" **Friend 1: "No, she already exists. She's in my physics class, and I've been trying to figure out how to ask her out." :) ...There ya go.
There's a flaw in your example. "She" refers to a specific person, while in your example Friend 2 merely said "a woman like that", so no specific person is being talked about. Therefore Friend 1 cannot say "she" - that would be a mistake - but should rather say "there is such a woman..." or "such a woman already exists...".
I know I am coming late in the discussion but let's try this. Somebody would be quoting the French poet Verlaine and starts: "Je fais souvent ce rêve étrange et pénétrant D'une femme inconnue, et que j'aime, et qui m'aime Et qui n'est, chaque fois, ni tout à fait la même Ni tout à fait une autre, et m'aime et me comprend.." And his friend interjects: "She already exists for me". But, more often than not, it's used about objects that are feminine in French. Examples have already been given in previous posts. That's why the English translation: "It already exists" is perfectly valid.