How do I know if my spouse is hiding money?

If you don't know what assets are out there, how can you determine a fair outcome? No fair outcome (whether through an out-of-court settlement or a trial) can be reached without a diligent disclosure by each side.  

That's why we have discovery.  Discovery is the process by which each side can force the other to provide a full disclosure.  Discovery tools include:

• Interrogatories: Up to 30 questions the other party must answer in writing, under oath.
• Document Requests: An unlimited number of requests for specific types/categories of documentation (e.g., bank statements, emails, etc.).
• Requests for Admission: Up to 30 statements the other party must affirm or deny, one-by-one.  
• Depositions: An opportunity to sit the other party (or a witness) down in front of a court reporter, to answer questions face-to-face, under oath.