Seeing is believing

Từ điển tiếng Anh - Cambridge Advanced Learners Dictionary

Seeing is believing. idiom saying
said to mean that if you see something yourself, you will believe it to exist or be true, despite the fact that it is extremely unusual or unexpected
• "I never thought Simon would get out of bed before lunchtime on a Saturday, but seeing is believing!"
Thesaurus⁺: ↑Using the eyes ↑Eyesight, glasses and lenses ↑The eye and surrounding area ↑Perceptive ↑Believing
Main entry: see_idiom