seeing is believing
眼见为实，只有亲眼看到才会相信
口语·表达亲眼见证后的信服
英文释义
to believe something only when one sees it
例句
I never thought she could run that fast, but seeing is believing.
典故来源
源自拉丁语谚语，强调亲眼所见比道听途说更可信，16世纪在英语中广泛使用。