Is "that" optional in these sentences? If not, does each mean the same?

Question

My experience working in the justice system and first year of law school have convinced me that my legal future lies in criminal litigation.

OR

My experience working in the justice system and first year of law school have convinced me my legal future lies in criminal litigation.

Are both grammatically correct?

Answer 1

Yes, they are both grammatical, and mean exactly the same.

Particularly in a complex sentence like that, it's probably clearer to include 'that'.