Learn Dutch: Ik kom echt, hoor. - I really am coming, you know.

Dutch does not have an exact match for the English -ing form. The simple present tense ik kom translates to both I come and I am coming depending on the context.

Does hoor mean hear in this sentence?

It comes from the verb horen which means to hear, but at the end of a sentence like this, it acts as a little filler word. It adds a reassuring tone, very similar to adding you know or believe me at the end of an English sentence.

Is hoor required here, or can I leave it out?

You can leave it out. Ik kom echt is a perfectly fine sentence meaning I really am coming. Adding hoor just makes your statement sound a little softer and more natural.

Why is echt placed after the verb kom?

In Dutch, adverbs like echt which means really, generally go after the verb. So while in English you might say I really am coming, in Dutch the word order is literally I come really.