I feel sorry about you.
I am regretful about your child. I understand how difficult such a situation might seem. Please, receive my heartfelt apologies.
I'm apologetic for your child. I understand how challenging such a situation might seem. I kindly request, take my heartfelt regrets. I truly regret the inconvenience brought about. I feel expecting that your child will forgive me.

Translation of sorry little one in French Reverso Context