Onun sevdigi kiz benim

The girl who he loves is me.

when I saw the sentence I thought it was ´the girl who he loves is mine´ - wouldn´t it be ´ben´ for ´me´ or am I getting muddled?

kişi ekleri  (personal endings)                        

ben-im  i am /be(V3) + me

sen-sin  you are /be(V3) + you

o           he/she/it is /be(V3) + him/her/it

biz-iz     we are /be(V3) +us

siz-siniz  you are /be(V3) +you

onlar     they are /be(V3) +them

iyelik ekleri (possessive suffixes)

ben-im  my

sen-in   your

o-nun    his/her/its

biz-im    our

siz-in     your

onlar-ın   their

 No,that wouldnt be "ben" since the suffix for person -in this case "I" - has to be put in the end.   .................benim.

 Example : Konuşmak istediğimiz kişi sensin.

               The person whom we like to talk is you.

That made me think... Could the sentence "the girl, who he loves, is mine" be translated like this? (using -dir suffix)

Onun sevdiği kız benimdir.

Mine means "benimki" but it can be translated in this case as "benim" So your translation is correct.

Benimki geliyor

Mine is coming.

O kalem benim(dir).

That pencil is mine.

I guess in English you don´t use "my" at the end of the sentences and you use mine.

You say "It is mine" instead of "It is my"

But in Turkish we use equivelant of "my" at the end of the sentence. "my" means "benim" in Turkish. We translate "benim" as "mine" to English when it is at the end of the sentence. Actually "mine" means "benimki" in Turkish.