Translation

確かめる / 突き止める / 確認する

Meaning

Ascertain means to find out or confirm something by checking carefully. It is more formal than find out and suggests reliable information, not a guess.

Examples

• 調査員は、火災の原因を突き止めようとしました。
  Investigators tried to ascertain the cause of the fire.
• 注文を発送する前に住所を確認してください。
  Please ascertain the address before shipping the order.