The answer mentioned above is correct, just explaining it, because a lot of users get stuck on this lesson:
The expected outcome for this exercise is:
I love 'Chocolate'\'Butterscotch' ice cream.
In between the words Chocolate and Butterscotch, we have an ending single quote, then a backslash, and then an opening single quote. All these three needs to be escaped.
Hence it becomes \' to escape the opening single quote, then \\ to escape backslash and at last \' to escape the opening single quote. Hence it becomes \'\\\' between the words Chocolate and Butterscotch.
let x = 'I love \'Chocolate\'\\\'Butterscotch\' ice cream.';
// log the variable
console.log(x);
Hope it helps.