Does this mean "she clearly remembers her departure" or "she remembers her departure clearly"? It seems to accept both but they don't mean the same thing...
Because "sin" indicates it's the subject's departure, not someone else's. So it can only be "her departure" in this sentence.
So, how would the translation than be of ' she remembers his departure' ? Hun husker hans afrejse?
Yes :) And if she remembers another female person's departure, it would be "hendes afrejse".