If you want to test the level of Trust you have built with a customer, ask yourself this question:
How often does your customer confide in you?
If the answer is never, then you have some series work to do in building a trust based relationship. If the answer shows that on many occasions a customer has actually confided in you personal or business concerns and requested your opinion or guidance on the concern – then you have established a trust based relationship.
People do not ask strangers or people they don’t trust for personal or professional advice because the risk is too great. When a person (customer) trusts you, they will have lower fear levels and will make themselves vulnerable with their actions. This is high risk stuff particularly corporate type people or managers.
Listen to your customers, give them high level content, and confide in them about your concerns! This shows you are human and not some corporate robot sent to sell them something. In other words, the fastest way to be trusted is to trust others first.