Can't add .fadeIn effect

Can't add .fadeIn effect

Any jQuery experts here?

if(msg == "OK")
{
result = '<img src="/images/sent.png"><br />Your message has been sent';

$("#fields").hide();
$(this).html(result);

}

I spent several hours trying to add .fadeIn effect to the result so that the result doesn't appear immediately, but fades in. No success. Can somebody help? Thanks.