2 Corinthians 13:1 – Every matter must be established by the testimony of two or three witnesses. (NIV 1978)
My Musings – One person can deceive, so we should not take action. Two or more can still conspire to deceive, so the matter still must be established. But the deceit among conspirators is more likely to unravel due to inconsistencies in their stories.
My Advice – Take no action and form no firm opinions based upon what only one person has told you. Wait for corroboration of at least one more witness or other evidence. You will be less likely to take actions that you will live to regret.