Why should I apologize to you?
I must apologize to you for breaking the vase.
I must apologize to you for not writing for so long.
I must apologize for the delay.
Please make my excuses for absence to your mother.
I can't apologize enough.
I'd like to say a few words by way of apology.
I wish to say a word of apology.
We are very sorry that your order was damaged.