Certainly
Surely
adverb
This is an adverb, but it has the same meaning (basically) as the kanji. It means certainly, and it can also mean surely.
The reading for this one is certainly weird. To remember the reading for this word, just think how you're certain that if you stash the treasure, nobody will find it here.
それは確かにそうですね。
That is certainly true.
彼は確かにリーダーに向いていると思います。でも、時々言葉がきついのがネックです。
He is certainly a good leader. But the problem is that sometimes his language is too harsh.
コウイチが百メートルほど飛ぶのを、この目で確かに見ました。
I'm certain I saw Koichi fly about one hundred meters with my own eyes.