This discussion is completely meaningless.

His meaningful gaze made me uneasy.

He is majoring in semantics at university.

My grandfather recently started participating in the Internet Elderly Association.

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

He knows that pain through his own experience.

He is feigning ignorance about that problem.

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

God only knows what he is thinking.

I have no way of knowing what he is thinking.