"Hostile" means unfriendly, aggressive, or antagonistic.
The opposite is "Friendly," meaning kind, warm, or welcoming.
"Joyful" refers to happiness (not exact antonym).
"Helpful" is positive but not directly opposite to "hostile."
"Persuade" is an action verb, not opposite in meaning.
"Violent" is actually a synonym, not an antonym.
\[
\Rightarrow \boxed{\text{Friendly}}
\]