By the way the "i" it's always with capital letter so you should always write "I", even in the middle of the sentence.

"I hope you will be satisfied <em>with </em>my assignment."

Hi!
I sent an email to my professor. I wrote this sentence:
"I hope you will be satisfied with my assignment"
Is it correct or not?

As Sophia said, "I" is always written in capital.

A sentence starts with a capital letter and there should be a full stop (or question mark etc.) at the end of a sentence.

Next question you have, post it in Answers session:

http://www.italki.com/question/add

I hope you will like my assignment.