Just move, on.
The thing is: "expectations" a person has upon another... is not going to happen. UNLESS it is realistic and doable.
This is not doable... your "friend" or whoever you are talking about, is NOT going to apologize, nor is capable and probably will never do so, and will not not not... do what you want as far as her apologizing and for everything she does.
So don't... expect it.
Don't expect... an apology.
It will not happen.
Move on.
The person you are talking about, is toxic or whatever. And "your" expectations of her/his behavior, is simply, not how they are.
And some people just NEVER believe nor understand, anything like an apology. They are, of a different... mentality. Not yours.
Why even fester about it.
You... want your friend to be a certain way.
She/he is NOT how you envision he/she should be.
But you can keep hoping that person will do and be and say as you think he/she should.
Or, you realize that not all people have the same courtesy as you.
Some people will never ever, be apologetic nor nice nor responsible for their own actions nor for the damage they do to others.
So you either stay hinged onto that person and dependent on them... or you unhinge yourself from their dynamic and don't make it your, issue.
So then you move on and don't associate with that person, or you keep doing so and keep being in their vicious cycle, knowingly.
And, even if this person apologizes to you... IS that, going to be enough??? Or will this person have to apologize to you, exactly as you think he/she should, and if not, it is not good enough and not valid for you?
I have known people, that EVEN if you apologize to them... it is NEVER ever, good enough. Because, it is not perfect enough for what THEY think an apology should be in their mind.
So then, people stop even apologizing to the recipient of the apology, because they don't ever, accept it because it is never, good enough nor executed good enough, for what they think, it should have been.
Vicious cycle.
Forgiving someone... is NOT contingent upon IF they apologize to you or not.
And, some people can never forgive anyone, EVEN if that person has apologized to them, a thousand times and meant it.
And if this person is mean, as you say, then YOU have the choice. Keep being around them, or not.
Being a PART of their toxic dynamic, or not.
Taking everything they do personally, or not.
Relying on that person to validate you or not.
Acknowledging this person is not your cup of tea, or not.
Choosing this person as someone you rely on or not.
Expecting them to do something that they will never do, or not.
And then, so if this person apologizes to you.
Then what?
She WILL go on and do other things that disagree with you and will NOT be the way you think she should be.
So then, EACH time you feel, she should apologize, is that going to ever be enough?
You want, that apology.
But if you get it, then what?
She will not change.
Some people will NEVER change and are not capable of being better and are not capable of even realizing they are icky. And they never will be, other than what they are.
So then what?
Is a thousand apologies, going to be enough?
You said this person has never acknowledged that her/his behavior is "wrong." Well, to you its wrong. And to others. But that person herself, does not EVEN know that. And has a million excuses for it. That is the way that person is.
Some people will NEVER realize, they are "wrong."