The purpose of the book Marriage Is a Commitment Shattered by Dishonesty is to highlight the importance of honesty in a marriage. It shows that trust is the foundation of a strong relationship, and once dishonesty enters, it can damage or even destroy that bond. The book aims to make readers aware of the consequences of lying, secrecy, and betrayal, while encouraging couples to communicate openly and remain truthful. It also teaches that marriage requires commitment, respect, and integrity in order to succeed.