If I hadn't seen it with my own eyes I wouldn't have believed it.

要不是亲眼看见了，我不会相信的。

《牛津词典》

You won't believe this, but I saw it with my own eyes.

你不会相信的，但我亲眼看到了。

youdao

I saw the accident with my own eyes.

我目击了这次事故。

《新英汉大辞典》

In his book, Bogle described the investment industry exactly as I was seeing it with my own eyes.

FORBES: Why I Index by Rick Ferri

You think you have HOUSES. In Notting Hill they have HOUSES. I have seen them with my own eyes.

NEWYORKER: Magda Mandela

But having seen the Sun again with my own eyes, it seems there is light at the end of the tunnel.

BBC: Surviving the worst winter in the world