Why I want to study English

There are many reasons why I want to study English. I'd really like to get to know people from different countries. And I hope that I'll be able to use English for my job one day(I'm still a university student though). To be honest, I'm really bad at English, but English broadens my horizons. That's why I want to study English.

(good luck with learning English! You're pretty good!)

Why I want to study English

There are many reasons why I want to study English. I'd really like to get to know people from different countries. I hope that I'll be able to use English for my job one day (I'm still a university student though). To be honest, I'm really bad at English, but English broadens my horizons. That's why I want to study English.

This was very good, I feel a bit picky but try to avoid starting sentences with the word "And". 

Why I want to study English

There are many reasons why I want to study English. I'd really like to get to know people from different countries. And I hope that I'll be able to use English for my job one day (I'm still a university student though). To be honest, I'm really poor bad (Poor is fine, but bad is more common.) at English, but English broadens my horizons. That's why I want to study English.

(Your English is actually really good!)