My basic advice from practicing architecture is to consider behaviors indicating a lack of trust a red flag when talking to
potential clients.
At best, it's a sign that the potential client is out of their depth in terms of experience dealing with professional services. That is to say that good potential clients for professional services tend to have used similar services before. Potential clients with unrealistic expectations who become actual clients make their unrealistic expectations your problem.
At worst, and perhaps more typically, people tend to project their character onto other people. People with less inhibition to not pay/deliver tend to act as if I am going to rip them off. A person who fundamentally views business as the process of extracting as much as possible from everyone is going to approach me as if I held the same view of misaligned interests.
After many years I developed a simple test. I require a retainer paid upfront and applied against final invoice. Logically, a willingness to write checks to me is a premise of the agreement for services. The ability to write a non-bouncing check for my services is also part of the deal. And a potential client who balks at writing a check upfront indicates a lack of trust that over the long haul may not be worth trying to overcome.
Good luck.
