Function - stringify

stringify - serialises javascript objects to JSON
JavaScript also has a built in function for converting an object into a JSON string.
This is a convenient way of showing an object that might not be displayed correctly.

var myArray = [ [1,2] , [3,3] ] 
console.log(JSON.stringify(myArray)); 

// Parse the JSON so we can access what we need. 
var parsed = JSON.parse(json); 

// Get the amount of objects inside 'watson_tone' so we can loop through each one.  
var count = Object.keys(parsed.watson_tone).length; 

// Make some strings to include in our output. 
var tableHeader = "<table><tr><th>score</th><th>tone_id</th></tr>"; 
var tableContent = ""; 

// Loop through the JSON and output each row in to a string. 
for(i = 0; i < count; i++) { 
    tableContent = tableContent + "<tr><td>" + parsed.watson_tone[i].score + "</td><td>" + parsed.watson_tone[i].tone_id + "</tr>"; } 

var tableFooter = "</table>"; 

// Get div and output the HTML. You can include these HTML strings straight in to your emailText variable. 
document.getElementById("your_table").innerHTML = tableHeader + tableContent + tableFooter;