"He loves his wife."
Translation:Han elsker kona si.
The word order changing whether it is demonstrative or not is a bit confusing
Agreed, that is one of the many things that trip me up. And I'm still trying to determine if there is a time to use one order over the other.
'Fruen' means wife too? I accidently wrote 'frauen' , I'm learning german too and i think i'm a little confused xD but now i learned a new word!
"Frue" (m/f) is another word for wife, yes. It's less used, and a tad old-fashioned.
"Fruen" is the definite form.
Sin/si/sitt/sine are used when: 1) The subject is a third person noun (he/she/it/they/Someone's name) 2) The possessive is referring back to the subject.
"He loves his car" - "Han elsker bilen sin." (subject is third, possessive refers to subject) "I love his car" - "Jeg elsker bilen hans" (subject is first not third, possessive refers to another person)
Hope this helps.
Edit: Added "someone's name" to point out they don't have to be pronouns
Since the feminine version 'kona' is used, you use the feminine pronoun 'si'. I know in some places the use of the feminine is declining, and being replace by masculine. I'm not sure if the word 'kone' is affected by this, but if so it would be 'Han elsker konen sin'.