I originally didn't have to tell you this.
This sentence is a high-level phrase commonly used by both men and women.
It is often used when one is suspected, and the suspicion is quite accurate, to take initiative and end the conversation with this sentence after explaining, giving the other party an illusion of "I could have hidden it from you, but I chose not to deceive you."
But the real meaning is: yes, I know you might be upset but I did it anyway.
At the end of the day, it doesn't represent a reluctance to deceive, but rather an acknowledgment that one can no longer keep it hidden, just like a death row inmate's confession is not truly remorseful, but because they are afraid of the punishment to come.
And when used, depending on the confidence of the speaker, it can produce varied effects.
When the speaker reaches a certain level of righteousness, they can cast a "guiltless" enchantment, which might cause the listener to feel a degree of guilt and shame.
