Dear [Name],
I am writing to apologize for my unacceptable dress at [event]. It was never my intention to offend or disrespect anyone, and I regret that my choice of clothing caused any discomfort.
I understand that the dress code for the event was [describe dress code], and I should have been more mindful of that. I understand that I should have been more considerate of the other guests and their feelings. I am sorry for not being more aware of the expectations and for not adhering to them.
I understand that my actions were inappropriate and I take full responsibility for my mistake. I am deeply sorry for any embarrassment or discomfort I caused. I will be more mindful of my clothing choices in the future and will make sure to follow any dress codes that are in place.
I hope that you can accept my apology and forgive me for my mistake. I understand if you are unable to do so, and I will accept whatever consequences come my way.
Sincerely,
[Your Name]