"her husband reads a book."
Translation:Ο άντρας της διαβάζει ένα βιβλίο.
The man reads her a book=Ο άντρας τής διαβάζει ένα βιβλίο, with τής having an accent mark.
Thanks, I presume there's no difference in pronunciation, so you'd have to infer from the context which meaning is meant when spoken
Actually there is a difference in pronounciation. Ο άντρας της διαβάζει sounds like ο άντραστης διαβάζει whereas ο άντρας τής διαβάζει sounds like ο άντρας τησδιαβάζει. It's difficult for a learner to understand the difference, I presume, but for a native it's very easy, and does not rely on context.