Hi Jun, I have currently received your email regarding to your being sad by failing the exam for two times. 我收到你的邮件,得知你对两次考试的成绩不理想而感到困扰。As your best friend in school, I definitely feel confident on your abilities in studying. 作为你学校里最好的朋友,我对你的学习能力十分有信心。I know how hard you are experiencing right now, but failing the exam does not necessarily mean that you are doing a bad job. 我明白你现在一定过的很不开心,但是那两次考试并不代表着你学习学得不好。What I have seen so far tells me that you are not only smart, but tough! 我所知道的你不仅聪明,而且还很坚强!I know you are strong, and so do you. 我知道你是很强,这点你自己也很清楚。The failure is only a small obstacle and you can learn from the lesson. 这次失败只是你前进道路上的一个小障碍而已,你可以从中吸取教训。Just believe in yourself, and I will back you at any time. 相信你自己,我会在任何时候都支持你! Yours,Jie 请你别太在意内容。语法没错误,尽管拿去交作业吧。