Because life had nothing planned for them, they don't expect anything from life.
That's why Chrystèle Burrel and Christophe Gérard, despite their total lack of education and moral values, go from place to place, from job to job as home help, with a carefreeness and joy that the rest of us could only dream about.
For them, life is sweet. It's become even more sweet, for up until they met each other, they were never able to trust anyone and weren't even aware that they could. Now that they've found each other, they don't want to lose each other.
Nevertheless, he's not the smartest or most dependable guy around, her Chris. And it really must be true love that he feels for his Chrystèle to be able cope with the way she cheats on him.
Yes, even among creatures of this kind, love exists. And when there's love, it's so easy to just trust...