When life's reality comes they find things in each other's characters that perfectly startle them. Every day reveals something new and something unpleasant. The courtship character fades away, and with it the courtship love. Now comes disappointment, sorrow, regret. They find that their characters are entirely dissimilar.
Married life is a burden full of cares, vexations, and disappointments.
Yes, marriage is a lottery. They know it. Some may get prizes and some may not. No one knows before he draws whether he will draw a blank or a prize. This is their conclusion.