Is this sentence natural?

It’s hard to describe the joy inside me.

Question

Is this sentence natural?

It’s hard to describe the joy inside me.

Answer

It's hard to describe the joy inside (of) me.  Sometimes some English speakers add (inside of me).. both are correct.

Answer

Yes.  Here are some other ways to express the same thought:

Words cannot describe the joy...
I feel an indescribable joy... (or "ineffable")
The joy I feel is beyond words.

Answer

I think it's sounds fine. Providing more context would help to suggest a better alternative.