Anne Hathaway doesn’t have a strong enough voice to sell I Dreamed a Dream as a song by itself. But she has infused her Fantine with what it takes to sell it as an expression of her character’s anguish.
An anguish that’s fed with self-loathing.
Fantine has been failed by the man who seduced her and then ran out on her and their child. She has good reason to suspect she’s being failed by the people she’s paying to take care of Cosette. She’s failed by the women she works with who ought to be her friends and protectors but who, because of a system of every man and woman for his or herself that has turned the people against each other, see her as competition to be eliminated. She is failed by the man who is, abstractly, her benefactor, Valjean, who, in his new identity as the benevolent and beneficent Mayor Madeleine, is so caught up in the business of being a good employer and philanthropist he has lost sight of the individuals in his employ and in his care. And she is failed by fate---or is it God?---when a chance arrival distracts Valjean at the moment Fantine is most in need of his help. But finally and most heartbreakingly she fails herself.
Fantine knows who is to blame for her troubles and to what degree, they’re at fault, but she can’t help faulting herself most at all.
Hathaway’s performance is more than a matter of letting her hair get chopped off and submitting to be photographed at unflattering angles. She fills Fantine’s eyes and then her face and ultimately twists and racks her whole body with the growing pain and terror of a soul turning against itself.---from my Second Miserable Thought: The hell she’s living.