Truth
Reality
noun, の adjective
The kanji and the word are exactly the same. That means they share meanings as well.
じつ
The reading is the on'yomi reading, same like you learned with the kanji. That is the truth, I promise.
実は、わたし、こうみえてもオリンピックに出たことがあるんです。
Well actually, even though I don’t look like it, I used to be an Olympian.
実のところ、おれたちはお前の実のおやじゃないんだよ。
To tell you the truth, we are not your real parents.
すまない、お前。実は、俺達の貯金を全部、プロ野球カードと風船ガムにはたいちまったんだ。
I’m sorry, Honey. The truth is I spent all of our savings on baseball cards and bubblegum.