The word "bell" shows up in the middle of embellish, and bells are something that decorate, or embellish something, making it more attractive. If you embellish speech, though, it can get ugly if you add a lot of details that aren't true.
Embellish often has the positive meaning of adding something to make it more handsome or beautifully decorated. But, while adding bells to something looks great at first, after a couple of hours of bells ringing in the ears, what was meant to embellish and beautify can get annoying. That's what can happen when you embellish by adding too many false or exaggerated details to a story. Embellishing with true, colorful details and vivid descriptions is what can really enhance the beauty of a story.