There is great potential in this story, but the English needs some tightening up and some tweaking. Not sure about the ending -not because I don't like a twist in a story, but because "The only mistake he had done (made would be better) was that he had started loving himself." doesn't gel with what he had been learning through the friends he had made. Try out some alternative endings. One might involve cutting to where Sara abandoned her friendship… perhaps an arranged marriage cut her off?