You can only get this assurance if both parties have had independent legal advice.

When you're doing your own negotiations and financial calculations, you might not be inclined to review your ex's net family property statement with a critical eye. An ex may intentionally, or inadvertently, exclude certain assets from their net family property, or they might undervalue these assets.
Valuations cannot always be accepted at face value- you need to request confirmation that all entries on a financial statement are accurate. If your spouse owns a business, for example, it can be difficult to accurately value what the business is worth without professional assistance.The real value of having a lawyer advise you on the financial aspects of a separation agreement is confidence in knowing that the settlement you receive (or the settlement you pay), is fair and based on the law.
People don't always appreciate the legal ramifications of signing a separation agreement.