I am writing to apologize for my poor performance in [task]. I understand that my performance was not up to the expected standards and I take full responsibility for it.
I am aware that my poor performance has had a negative impact on the team and I deeply regret that. I understand that I have let you and the team down, and I am truly sorry for that.
I want to assure you that I am committed to improving my performance and I am taking steps to do so. I have identified the areas where I need to improve and I am working on them. I am also taking the help of my colleagues and mentors to ensure that I can improve my performance.
I understand that my poor performance has caused a lot of inconvenience and I apologize for that. I am committed to making sure that this does not happen again and I am taking all the necessary steps to ensure that.
I understand that I have to work hard to regain your trust and I am willing to do that. I am confident that I can improve my performance and I will do my best to make sure that I can do that.
Once again, I apologize for my poor performance and I assure you that I will do my best to make sure that this does not happen again.