It's better for him not to know the truth. After all, ignorance is bliss.

He is feigning ignorance about that problem.

He knows that pain through his own experience.

I have no way of knowing what he is thinking.

He is working hard to make his abilities known to the world.

In order to understand his feelings, I had a deep conversation with him.

God only knows what he is thinking.

He owns the old stock of that company.

There is a big tree stump in the garden.

He always pretends to be a 'nekokaburi', deceiving people.