In fact, I dont know him at all.

实际上，我一点也不认识他。

youdao

I know him, but we dont frequently see each other.

我认识他，但我俩并不常来常往。

《新英汉大辞典》

I dont know where Ive seen him before.

我不晓得在哪儿见过他。

youdao

I dont even know him, let alone falling in love with him!

我根本就不认识他，更不用说爱上他了！

youdao

I dont even know him, let alone falling in love with him!

我根本就不认识他，更不用说爱上他了！

youdao