Final answer:
The secret to the stability of Japanese marriages as presented by Nicholas Kristof is linked to the cultural perspectives on divorce, where societal expectations encourage couples to remain together.
Step-by-step explanation:
According to Nicholas Kristof, the strength and stability of Japanese marriages are linked with cultural views regarding divorce. Japanese couples often remain married even during difficulties, contrary to the occurrence of fraternal polyandry or polygyny which are practices observed in other cultures. In Japan, cultural norms and expectations around marriage focus on the permanence and societal roles within the marriage rather than the romantic aspects. The expectations and views of society lead to a stigma associated with divorce, resulting in a higher tendency for couples to remain married, despite challenges.