A more thorough explanation:

Definition: A marriage based on a misrepresentation regarding some issue of fundamental importance to the innocent party, who relies on the misrepresentation in the decision to marry. The misrepresentation must concern something of fundamental importance to a marriage, such as religious beliefs, the ability to have sexual relations, or the ability or desire to have children.

Example: John tells Jane that he wants to have children and they get married. After the marriage, Jane finds out that John had a vasectomy and cannot have children. This marriage is considered fraudulent because John misrepresented his ability to have children, which was a fundamental issue for Jane in deciding to marry him.

This example illustrates how a fraudulent marriage is based on a misrepresentation that is essential to the decision to marry. In this case, Jane relied on John's statement that he wanted to have children and would be able to have them. If she had known the truth, she may not have married him.