This is the 275th most frequent Japanese word.
実は
"Actually" or "to tell the truth."
In this case, '実は' is used to disclose unexpected information in a softer tone to the listener.
実は、彼女はまだ学生なんです。
Actually, she is still a student.
Here, '実は' is employed to reveal a fact that might not be immediately obvious.
実は、去年日本に住んでいました。
The truth is, I lived in Japan last year.
In this context, '実は' introduces a confession or disclosure, often inviting the listener's interest.