One feels your pain, Yvonne! It's hard to make sense of either the English or Turkish versions of this sentence. Is the contributor trying to say that she wants "this" regardless whether others want it or not? To translate the Turkish as "She wants this for herself" would not seem right, because back-translation would give us "O bunu onun için istiyor"--or so it would seem. Further explanation appreciated.
I guess (just guess) that it's like : she wants it herself For example i want to buy somebody a birthday gift and i know she likes X then my brother taps on my shoulder and says "come on , she ain't gonna like X , don't buy her that on her birthday" and my answer will be "o bunu kendi istiyor/seviyor."
Possibly if kendi belonged to onu then it would be onun kendisi. There has been a set pattern throughout this course where the subject and the object are next to each other, the verb at the end, then everything else shovelled in just before the verb. I agonise with you. My mind is still trying to accept Turkish grammar.