how did mrs de winter in rebecca go from innocent to knowledge

Do you mean the narrator? Maxim De Winter's second wife and the narrator of the novel. The narrator works as Mrs. Van Hopper's paid companion in Monte Carlo until meeting Maxim and agreeing to marry him. Unsophisticated and timid, the narrator is insecure about her role as the mistress of Manderley and is overwhelmed by the constant reminder of Rebecca in the estate. As the novel progresses, the narrator becomes increasingly preoccupied with Rebecca and ultimately concludes that Maxim is still in love with her. After Maxim confesses the truth to her, the narrator is suddenly free from Rebecca's shadow and can assume her true role as mistress of the house and Maxim's wife.