in god we trust all others pay cash what does it mean

We trust God, others have to pay cash.

This is a joke. "In god we trust" is a very common religious motto and the national motto of the United States. The word "trust" is used here to make a pun. It originally means faith in religious mottos. It is deliberately used as one of "trust" here, which means that we believe that God will not owe money on credit, but others will have to. Paid the bill in cash.