I Like English

Before i don't like English.because of the exam.so i hate english.but now i like english very much.i hope I can speak English smoothly.

Correction and notes

I like English

First Pass - use I instead of i when talking about yourself. Also you are talking about the past so don't should be didn't.

And also "I hate" is the present, you are talking about the past - so "I hated"

And use a capital letter for a proper name - in this case English

Before I didn't like English.because of the exam.so I hated English.but now I like english very much.I hope I can speak English smoothly.

Second Pass - leave a space after a punctuation mark.

Before I didn't like English. because of the exam. so I hate english. but now I like english very much. I hope I can speak English smoothly.

Third Pass - what are the sentences. It is ambiguous.

Could it be

a) Before I didn't like English because of exams. So I hated English. But now I like English very much.

b) Before I didn't like English. Because of exams, I hated English.

a and b are basically two ways of saying the same things with only subtle differences.

Fourth Pass

I hope that I can speak English fluently.

I believe that fluently is the word that you want here. It conveys more than smoothly which gives a sense of rhythm rather than understanding and ability.

So my suggested correction ( with a slight addition to the final sentence).

Before I didn't like English because of exams. I hated English but now I like English very much. I hope that I will be able to speak English fluently.

I Like English

Before, I didn't really like English because of the exams. So I hated English. But now, I like English very much. I hope I can speak English fluently.