Learn Dutch: Sorry, het spijt me heel erg.

In Dutch, you do not use the verb "to be" (zijn) to say you are sorry. Instead, you use the fixed phrase het spijt me, which literally means "it regrets me".

What is the purpose of the word het in this sentence?

Het means "it". In this phrase, "it" is the subject of the sentence and refers to the situation or the mistake you made. You are saying that the situation causes you regret.

I see the words heel erg. Doesn't erg mean "bad"?

Yes, on its own erg means "bad" or "terrible". However, when used together to describe a feeling or action, heel erg translates to "very much" or "really". Here, it emphasizes the apology, meaning "I am very much sorry."

Why does the speaker say both Sorry and het spijt me?

It is a common way to make an apology stronger. Sorry is used just like in English for a quick apology, while following it up with het spijt me heel erg shows genuine, deep regret.