To Confirm
To Verify
する verb
確認 is confirmation. When that's a verb, you have to confirm or to verify.
かくにんする
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. It will help immensely if you know the word 確認 already as well.
我が社がついに赤字を脱したことを確認した時、私は胸を撫で下ろしました。
I was so relieved when I confirmed that our company finally got out of the red.