Spanish phrase
No necesitas ~.
Meaning
You don't have to ___.
When to use it
States an action is not required to calm someone. Commonly used to comfort someone who is anxious; tone can be casual or polite depending on phrasing.
Example dialogue
No necesitas preocuparte, todo saldrá bien.
You don't have to worry, everything will be fine.
Gracias, me tranquiliza.
Thanks, that reassures me.