I would argue that our protagonist, Florentine Lacasse, was isolated from the life she wanted rather than being isolated in the sense of being lonely. She is part of a huge family with her eleventh sibling being on the way, but the family is extremely poor, and many of her siblings do not even have necessities like shoes. Florentine dreams of breaking free of the shackles of poverty and climbing the social ladder until she is able to live a comfortable life surrounded by high society, rather than by her impoverished family. In other words, she feels alienated from her family as a result of her aspirations.
Florentine briefly believes that she has found everything she has been looking for when she meets Jean Lévesque, who flirts with her at work and asks her out on a date. When he stands her up, however, her feelings of isolation and alienation return with force, and leads to her throwing herself at him, which ultimately has devastating consequences.
Finding herself pregnant after being raped by Lévesque, she turns to Emmanuel, Jean's friend who had fallen in love with her, and marries him not for love, but for his ability to provide for her and be deceived into believing that he is the father of Florentine's child.