The instructions from Dianette showing people who is who: who is beautiful, who is only pretty or good-looking or attractive.
This is how we speak about someone's beauty and good looks (information is taken from Longman Dictionary of Contemporary English):
beautiful is used to describe someone, usually a woman or child, who is attractive in a very special and noticeable way.
pretty is usually used to describe a girl or woman who is good-looking, with regular features. It can also be used to describe a boy or young man who has an attractive but feminine face.
handsome is usually used to describe a man or boy who is good-looking, with strong regular features. It can also be used to describe a woman, usually an older woman, who has attractive but masculine features.
good-looking can be used to describe anyone who you think is nice to look at.
attractive is used to describe someone who looks good in a way that attracts sexual interest.