Dear [Name],
I am writing to apologize for my unprofessionalism during our last meeting. I understand that my behavior was inappropriate and I regret that I did not act in a more professional manner.
I understand that my behavior was not in line with the standards of professionalism that you expect from me. I take full responsibility for my actions and I am sorry for any inconvenience that I may have caused.
I have taken the time to reflect on my behavior and I have come to the realization that I need to be more mindful of my actions and words in the workplace. I understand that my behavior was unacceptable and I am committed to making sure that it does not happen again.
I am also aware that my unprofessionalism may have caused you to question my commitment to the company and I want to assure you that I am still committed to doing my best work. I understand that my actions have caused you to doubt my dedication to the company and I am sorry for that.
I am committed to learning from this experience and I am determined to become a more professional member of the team. I am confident that I can regain your trust and I am willing to do whatever it takes to prove to you that I am a reliable and professional employee.
Once again, I apologize for my unprofessionalism and I am committed to making sure that it does not happen again.
Sincerely,
[Your Name]