I am writing to apologize for my unwarranted assumption about you. It was wrong of me to make assumptions about you without knowing the full story, and I am deeply sorry for the way I acted.
I understand now that I should not have made any assumptions without knowing the full context of the situation. I should have taken the time to talk to you and get to know you better before making any judgments. I realize now that my assumption was wrong and I regret the hurtful words I said.
I understand that my words may have caused you pain and I am truly sorry. I want to make sure that you know that I do not think of you in the same way as I did before. I now understand that you are a kind, compassionate, and understanding person.
I want to make sure that you know that I am committed to being a better friend to you and to not making assumptions in the future. I will take the time to get to know you better and to listen to what you have to say. I will also be more mindful of my words and how they might affect you.
Once again, I am sorry for the way I acted and for the assumptions I made about you. I hope that you will accept my apology and that we can move forward as friends.