Examples of using "„hm" in a sentence and their english translations:
Hmm, maybe!
You don't say much, do you?
Hm. Unfortunately, it's cold.
Hmm, do you really want to know?
Hmm. I have a feeling I'm going to get lost whichever road I take.
"Which girl in the class do you think is the cutest, Tom?" — "Hmm, maybe Maria." — "What? Maria? But she's really not very cute at all!"
For people who understand something about art, there is no need for words. One says "Hm!" "Ha!" or "Ho!", and with that everything is expressed.