There are no guarantees of honesty in any legal process. The Collaborative Family process relies on undertakings by both parties to make voluntary disclosure of all important information. However, from the outset both parties know that they have an obligation to provide full, honest and complete disclosure. This is part of the contract that both the parties and the lawyers sign at the start of the process. Furthermore, a Collaborative Family Lawyer is mandated to withdraw from the process if s/he feels his/her client is refusing to make full disclosure. Such a requirement serves as a disincentive to a potentially dishonest party, given that they would then be required to incur further legal fees in finding another lawyer and/or ending up at court.
Collaborative Family Law lawyers do not focus on rooting out hidden assets or income. Although you may see any financial documentation you feel is important, if you do not trust in the basic honesty of your spouse, Collaborative Family Law is likely not appropriate for you.
Remember that the cost to find hidden assets is often very high. Regardless of the process you choose, you will need to conduct a cost/benefit analysis and decide whether such a search is worth the expense.