The purpose of a negotiation is to reach an agreement between two or multiple parties on terms that all of these parties are willing to agree upon, but also are willing to uphold. If the parties to a negotiation do not trust each other-- which is often the case-- or do not trust the process, they're going to be even much more likely to either not participate in the negotiations, or, to not uphold the terms of the negotiated agreement that they have all agreed upon.