You don’t. Trust is only necessary when knowledge is unavailable. There should always be indicators but there can never be proof. For example the phrase, “I trust that I am aware of this sentence” is interpreted as “I know that I am aware of this sentence” and use of the word “trust” in that context may be interpreted as indicating that knowledge is a starting point for trust.

A more useful question might be “What do I know that gives me an indication that I can trust you?” I trust this is what you mean by your question.

For your answer, you can have no scientific proof because I am not confined to a lab and if you put me in one, I assure you the answer to your question will be, “No”.