"She deleted all her emails."
Translation:Hun slettet alle sine e-poster.
Well, I'm a bokmål user and I would also prefer to put "sine" at the end of the sentence both in writing and talking. (Without the har, as that interprets to She has deleted all...). Putting the possessive in front of the noun is more common among (older) people that prefer conservative bokmål (or maybe riksmål), in Oslo it was quite common to speak of Min mor (my mother) some 20-30 years ago, but nowadays most are saying Moren min (literally mother of mine). But the two mean exactly the same, they're synonyms.
Those that help? In Norwegian you will never be in doubt about whose car you are driving, because of the reflexive pronoun. She is driving her car = Hun kjører bilen sin / Hun kjører bilen hennes. Sin points back to the subject of the sentence (the car belongs to the lady driving, hun). Hennes is referring to a party not otherwise mentioned (the car belongs to some other lady, hennes -> her's).
Most verbs with the -et ending can also be written -a. -et is the preferred one in this course which follow the NTB language standard (a conservative bokmål). Few official sources will use -a as it is considered radical (it is used by the biggest working class paper Klassekampen).
But for unofficial use I think people's dialect will rule which form to chose. My dialect is a "working class dialect", more commonly referred to as a broad dialect (I come from an area with (historically) plenty of industrial workers, iron works, railroad, mills, timber floating, farmland etc). I say "sletta" and I write "sletta", I like to take advantage of the fact that I am allowed to correctly write pretty similar to how I speak. (My husband vetoed me writing "gifta oss" on our wedding invitations;-) I had to settle with "giftet oss".)
I am always amazed at how socio-economically relevant choices in written language are in Norway: it's really interesting, especially coming from Italy where dialects are relegated to the spoken, everyday life and a standardised language for written communication has been established centuries ago. Thanks a lot for your insight :)