in good faith
​believing that what you are doing is right; believing that something is correct
We printed the report in good faith but have now learnt that it was incorrect.
He bought the painting in good faith (= he did not know that it had been stolen).
信用して、誠意を持って、誠実に、善意で
e.g.
/fe3hdialogue/Constance×Hapi#62e26db1bdb0e50000025806