This is the 22nd most frequent Swedish word.
hon
"Hon" means "she" in English.
The word 'hon' is used as the subject of the sentence, referring to a female person performing the action of reading.
Hon läser en bok.
She is reading a book.
Here, 'hon' is used as the subject in the subordinate clause, indicating the female person expected to arrive.
Jag vet att hon kommer att vara där.
I know that she will be there.
In this case, 'hon' incorrectly replaces 'henne', which illustrates a common mistake due to 'hon' being nominative, but it was intended to mean 'her' in accusative.