本当を言うと (to tell the truth)

"To tell the truth, I'm afraid of heights." "Coward!"

To tell the truth, I'm not your father.

To tell the truth, he's not human.

To tell the truth, she no longer loves him.

To tell the truth, I think you're wrong.

To tell the truth, I'm tired of it.

To be honest, I'm not very knowledgeable about computers.

To tell the truth, I didn't go there.

To tell the truth, he's a famous lawyer.

To be honest, I don't have any money on me at all.

To be honest, I'm not really interested in sports.

To be honest, I couldn't solve this problem.