String.Insert() usage problem

Questions & Answers
1

Is there a reason why this code should not produce "aZZZbc"?

function testInsert(){
    var sentence = "abc";
    sentence.Insert(1, "ZZZ");
    print(sentence);
}
2

http://www.go-mono.com/docs/

String.Insert() returns a string, you need to assign it to something.

e.g.

sentence = sentence.Insert(1,"ZZZ");