Best practice to stringify a ValueMap

Hi guys,
Whats the best way to stringily a ValueMap .?
Currently i am using FileUtils to write the value map to a file and then using __String class to read from the file but i want to avoid the file writing operation as this task is happening multiple times in my game.
Cheers!

Can you show an example, please?

What i am doing right now is :

ValueMap mapInfo; // suppose mapInfo has a lot of data in it
FileUtils::getInstance()->writeValueMapToFile(filePath);
__String *str = __String::createWithContentsOfFile(filePath);

our required Stringified ValueMap is in str->getString()

I am asking for a different approach as the file writing operation is time consuming.