“How important is trust in establishing long-term business relationship?”
If you get yourself in a pickle, and the bank does not loan you money, and you need money to pay people, and if you have not been paying them ever since the company started, then they probably not going to care if your business goes bankrupt. They are going to want there money that you have not given them.
If you did pay the people that you buy from, or that do projects for you, and when you do have to file for bankruptcy, they will care that the source of money is going away. They probably would wait for you to get the money to pay them.
You should smile. Smiling lets the person know that you are friendly, and smart.