II would have written like thia, perhaps, bearing in mind that English is only my second language, I'm not fluent:

//

Dear Agnes,

It's been a long time since I last wrote to you. Firstly I have an apology to make, and secondly I want to tell you I'm coming back home. Yes, I've finished my education now, and am thinking about going back. I've also received a work permit showing I'm allowed to work there. I was away from home for a long time, and now it's time to see you again. You are /after all/ my best friend. I've also been working during the holidays so I'll be able to pay back what I owe you. I wish you the very best and see you soon. Your friend M. 

//

I've noticed that the English often throw in a couple of crosses xx at the end of personal letters, but I really don't understand when and why they use it, or to whom, but it seems it's to add more affection like a smiley or something. I hope someone fluent could explain. It seems handy but you wouldn't want to use it the wrong way, obviously.