Phrases Apologies and Excuses

I'm so sorry.

Meaning

A very strong expression of apology.

John: I am terribly sorry for what I did.
Alice: It's okay, but please try to be more considerate next time. <b>I'm so sorry</b> that I caused this situation.
John: Yeah, I feel awful about it. I will definitely try to avoid doing something like that again.
Alice: I appreciate your sincerity. I’m really trying to forgive you, but, <b>I'm so sorry</b> this has happened.