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.
この女の人は、私の実の母ではありません。
This woman is not my true mother.
プロフィールでは２５才と言ってるんですが、実は私３５才なんです。
My profile says twenty-five years old, but in reality, I'm actually thirty-five years old.
実を言うと私、こう見えてもオリンピックに出たことがあるんです。
As a matter of fact, I've been on the Olympics even though I may not look like it.