the most telling evidence
telling
/ˈte-liŋ/
adjective
carrying great weight and producing a marked effect : effective, expressive
verb
told the whole story to us
could never tell a lie
reveal disclose divulge tell betray mean to make known what has been or should be concealed. reveal may apply to supernatural or inspired revelation of truths beyond the range of ordinary human vision or reason. disclose may imply a discovering but more often an imparting of information previously kept secret.
idiom
—used with a statement to suggest that one is making the statement in an unwilling way