Accessing values on fields of a record thru suitescript is only limited there is an official list on Netsuite helpguide.

In the Scriptable Record Browser the recurrence field is not accessible, however the string value in that field can be access and a combination of multiple fields in the ‘task’ record.

Follow these steps to get the values of a record and put it in the Email templates using workflows

JSON (JavaScript Object Notation) is available for client-side Suitescript, another popular usage JSON is the ‘stringify’ method it is primarily used in converting JavaScript data structures into JSON text.

In Netsuite suitescript JSON.stringify(s) is available in client-side script. However in server-side suitescript you will get an error when calling this method.

As per Netsuite documentation, we can use nlapiEncrypt(s) and this will create and return string value using SHA-1 method.