I write to you because I would like to say sorry and ask for an apology for the incident that took place three days ago inside our office. I know how hard it is to have an officemate that hide grudges against you. To break the ice, I offer my apology.
I never really meant to harm your feelings and to embarrass the both of us in front of our fellow workers. It is just that I was overcome by my emotion thus the sudden outburst. I know you feel mad against me but let us bury the hatchet now.
To show you my sincere apology I would like to invite you for a dinner tonight at the restaurant of your own choice. I do hope that this letter of mine would appeal to you and would forgive me for what I have done.