My favortite favourite book

The Ffirst thing I learned is how important about friendship is. In the story, Amir’s best friend Hassan, he sacrificed his life in order to protect Amir’s safety.This plot(/action) touched my heart deeply.

And I also learned that we should brave to take our responsibility (or 'in taking responsibility', or 'in accepting responsibility'), B because about in this book, Tthe tragedy of the whole story is due to Amir’s father’s weakness, ; he doesn't have the courage to admit that Hassan is his son, and then the story (or 'trouble', to make it clear that's what you mean) begins.

That is why this book is important to me.

So:

My favourite book is The Kite Runner, because I learnt a lot from this book. 

The first thing I learned was how important friendship is. In the story, Amir's best friend Hassan sacrificed his life in order to protect Amir's safety. This action touched my heart deeply. 

I also learned that we should be brave in taking responsibility for our actions, because in this book, the tragedy of the whole story is due to Amir's father's weakness; he doesn't have the courage to admit that Hassan is his son, and then the trouble begins.

That is why this book is important to me.

Be careful about capitalisation and spacing. Capitalise proper nouns and the starts of sentences, and a space needs to follow a full stop. Also, it's best not to start a sentence with 'and' in formal writing. Book titles are underlined when written.

'Admit' is usually followed by 'that', eg. Although there were a few errors in your writing, I must admit that your English is not too bad at all. :)

From what I remember, I totally agree with you; The Kite Runner is a great novel.

Great job! If I've said anything confusing don't hesitate to comment and ask me (or whatever it is you're supposed to do on this website)