Apologies ~ E-mail Writing

Apologies
I’m sorry to have troubled/inconvenienced you.
I’m sorry that I didn’t get back to you sooner/earlier.
I’m sorry for making such a careless mistake.
I’m sorry for having kept you waiting so long.
I’m really sorry for having made such a thoughtless comment.
Sorry for the long delay in replying to your e-mail.
I apologize for having caused you so much trouble.
I would like to apologize for having taken so much of your time.
Please forgive me for my late reply/response.
Please forgive me.

Expressing forgiveness
Of course I forgive you.
I’m willing to forgive you.
Let’s put this incident in the past and move on.
After all, it’s not a big deal in the grand scheme of things.
I think that I’m partly to blame, too.
You’re not the one to blame.
Please don’t blame yourself.
It isn’t completely your fault.
It wasn’t your fault.

e.g
Hi Sally,
I’m sorry I wasn’t able to make it to your party last night. My boss called late in the afternoon and asked me to help finish an urgent project. I tried calling you but wasn’t able to get through. Anyway, I hope everyone had a great time. Please accept my sincere apologies
Yours,
Daniel

Dear Neil,
Sorry for the delay in replying to your e-mail. I looked over your suggestions, and I think most of them are feasible. If you don’t mind, I’ll forward a copy directly to the head of the budget committee. He might contact you if he has any questions. Keep up the impressive work.
Regards,
Daniel