Love And Hate Are One And The Same No? A Sherlock x Reader

Ice man?

You decided to go to an internet café to do some work because your flat was being painted a nice shade of (F/C). As you were tapping away at your laptop you sensed that someone was staring at you. When you looked up you noticed a man with an expression that looked like he had just tried a sour candy, possibly glaring at you. Honestly with look on his face you couldn't tell if he was mad at you or if he smelled something bad and happened to be looking in your direction. Being the polite person you are you smiled and waved but you had work to do so your attention went back to your laptop.
A few minutes later you heard the chair across from you scrape backwards, "I do hope you don't mind if I sit."
"Oh no no I'm fine with it."
"American? How quaint."
"That obvious?"
"Most defiantly. Now I have a business proposition for you."
You cock your head to the side. "Now what would a man I just met, who didn't introduce himself might I add, possibly want business with me?"
"Mycroft." You noted how he didn't extend his hand in gesture. "Now, I want you to spy on your neighbor Sherlock Holmes and his flat mate John Waston. I would compinsate you with a large sum of money of course."
"Now Mr.Mycroft why in the world would I do that? I just moved in and haven't even set up the Wi-Fi in the flat. Much less got all buddy buddy with my neighbors."
"Yet you've been to their flat and even held John's baby."
"How would you know that?"
"I have my resources. Now answer me will you take me up on my offer?"
"No."
"No? Now Ms.(L/N) I am only offering this deal one more time choose your words wisely."
"Mr.Mycroft even if I get to know them very well I wouldn't tell you that's not the type of person I am now I insist that you leave my table right now. Before I inform the waiter that you are harassing me in a way that is highly uncomfortable."
"As you wish I hope you have a lovely day (Y/N)(L/N)." With that he left and even exited the café.
As you sat thinking over what just happened your only thought was. How did he know my name?