Hej, min brudgom og smukt. doesn't make sense in Danish. Then again the Spanish original doesn't seem to be grammatically perfect.
In a dictionary Novio is explained more like a boyfriend than a bride's groom, which in Danish will be "kæreste". Guapo means beautiful or handsome (as you have translated) but to make a correct Danish sentence and to best preserve the Spanish sentence structure it would be "Hej, min kæreste og smukke" as the form "smukt" cannot be used here.