I was left with puzzlement as to the existence or nonexistence of God.

我对上帝存在与否这个问题依然感到困惑。

I would never choose nonexistence, like my wife.

我永远不会选择不生存，我妻子可能会，但我不会。

He brings things into existence from nonexistence.

他把事物从不存在带到存在之中。

However, I believe no one will doubt its nonexistence.

但我相信没人会对这样人的“不存在”产生疑问。

The gate of heaven is between life and death, existence and nonexistence.

在生与死、存在及不存在之间的地方就是天门了。