An Apology For A Really Dear Friend...

Hi guys, I know my story is long but it has been affecting me everyday so can you please read it. Thank you very much. I've been really good friends with a girl at college for more than a year. We always joke about and have a great time together. However, one day, me and her (can't tell name for confidentiality) went to our college library to study for an 'A' level exam which will be sitting in a weeks time from then.

Another friend of mine entered the library and sat next to us, he started making jokes about her accent which is really English (this is mainly due to the fact that she lives in a really roughed up area where no one talks "proper" English) so she started making jokes back to him about his overuse of slang in every sentence he says.

I couldn't help myself and burst out laughing (I know you are meant to be quiet in a library but still....), I laughed so hard that tears streamed down from my eyes.

Then she looks at me and jokingly slaps my face lightly to make me stop laughing, I wanted to make it even so I lightly patted her cheek with the back of my hand, she was immensely shocked by what I did and slapped me again with all her strength (I don't whine about getting hit usually but that second slap stung).

I didn't want to start a fight with her so I grabbed her gloves which were on the table and chucked it across the table instead of hitting her.

In return, she took my 'A' level book and chucked it on the floor. I sat at another spot in the library, a few moments later she grabbed my book and the gloves and left the library. I got the book the next day, but since the day that incident happened in the library she hasn't been talking to me.

I tried testing her during the half-term that I still wanted to be friends with her. She replied to me and said many things which really shocked me, she said things like: she thought I was the nicest guy she's ever met but then she was wrong, when I slapped her on the face her face was stinging with pain for 20 mins (I couldn't believe this because even the people around me said that I didn't slap hard at all, I myself knew I barely slapped her) she said I didn't realize my own strength and it scared her, another thing she said was that I was embarrassed to be around her when I was with my other male friends (this is not true, my other friends make immature jokes that we are both lovers and I retaliate whenever they said that sort of stuff).

The incident in the library happened towards the end of year 12, I later tried to talk to her face to face and she said that there is no room for reconciliation.

Another day after that incident, we were in the library doing homework as it was due next lesson, I didn't understand one question so I asked her, she didn't reply but gave me a really sharp "do I know you?" look.

Now I am in year 13, a few weeks have passed and we still don't talk to each other, I find it especially awkward since she is in all my lessons and she was the person that I sat next to and talked to most in all my lessons before the incident but now I sit away from her and we don't talk.

To be honest I still consider her to be my friend, I have even bought some gifts during my summer holidays for her, I haven't really given it to her yet but I intend to at the right time. 

Can you guys kindly give me some useful ideas for how to apologize to her and be friends with her again?

Thank you very much and may God bless you all!