He was not accustomed us to this writing style. Marc has matured; Perhaps it is less whimsical, less focused on humor. But for me this is the most profound of his novels. I do not deny provided "And if cétait true" which remained for years my favorite novel. I hope wholeheartedly that "Another idea of happiness" will also subject of an movie soon.
Do go with no a priori, let yourself be carried away by the meeting of these two women. Very soon you will believe you sitting at the back of their old Oldsmobile convertible to collect their confidences.