Why? Because they very seldom bathe and still smell like roses (or at least they never smell sweaty or horsey or unwashed). They never shave their legs but when the hero runs his hands up their thighs he doesn't notice how long the hair has gotten. And they never brush their teeth yet the hero doesn't complain about bad breath.
When you read (or write) an historical romance novel it's naturally focused on the relationship between the hero and heroine. Of course most writers research pretty much every aspect of the time period they're writing about which includes the daily habits of people. For instance, in the 14th century, where my current WIP is set, most people did not bathe every day and sometimes not even once a month, yet I would never dwell on this in my novel. It would detract from the essence of the story. And, let's face it, no one wants to read about a hero who smells like an unwashed horse and a heroine who has six inch leg hair and breath so foul a dog would turn away.
So, if you ask me, an Historical Romance Novel Heroine is the way to go. You get the most romantic guy on earth and he loves you even though the hair on your legs is longer than the hair on his head and he thinks your kisses are sweet as honey even though you have a snaggle tooth smile. What more could a girl ask for?