All that is very true. Where the author has certainly copied after nature is in the personality of Séverine. She is not a true criminal; sensual, depraved though still young, experiencing love only in adultery. Though deceitful, she is nevertheless a good wife and a good housekeeper up to the day where chance had thrown her into evil doing. She is united to her husband, and for that reason she becomes his accomplice in crime, without horror or dread; but afterwards, seized with love for Jacques, she experiences dislike for her husband and wishes to turn the lover into his murderer.
"The need increased in her of having Jacques for herself, all for herself, to live together, days and nights, without ever more parting. Her hatred of her husband grew greater, the mere presence of this man threw her into a morbid and intolerable condition of excitement. Tractable, and with all the amiability of a delicate woman, she became enraged at everything in which he was concerned; she flew into a passion at the least obstacle he put to her wishes.... The stupid tranquillity in which she saw him, the indifferent glance and manner with which he received her anger, his round back, his enlarged stomach, all that greasy dullness which has the appearance of happiness, made her exasperation complete. Oh! to go far away from him.... One day when he returned, pale and livid, to say that in passing before a locomotive he had felt the buffer graze his elbow, she thought to herself that if he were dead she would be free.... She would go with Jacques to America.... She who at other times so rarely went out now conceived a passion for going to see the steamships sail. She would go to the pier, and would lean on her elbow watching the smoke of the departing vessels.... [And at the decisive moment] she threw herself passionately on Jacques's neck. She fastened her burning lips to his. How she loved him and how she hated the other! Oh! if she had dared, twenty times already would she have done the deed ... but she felt herself too gentle, it required the hand of a man. And this kiss which would never come to an end, was all that she could communicate to him of her courage, the full possession that she promised him, the communion of her body. When she finally withdrew her lips nothing more was left to her; she believed that she had passed completely into him."