Page 159 - Patrick Moreau, Jean-Benoit Heron Marine Knots How to Tie 40 Essential Knots

In the middle of the nineteenth century, in the United States, when a whaler
was courting a girl that he was in love with, he gave her a special kind of
knot that she had to give back to him.

Depending on how she returned the knot to the whaler, it would convey
her feelings toward him.
If the knot was almost undone, the guy didn’t have a chance. If she gave
it back to him as it was, without tightening or loosening it, it meant that she
was just a good friend. However, if she gave the knot back to him tightened
with the two little hearts tied together, it meant that she was “spoken for,”
and that it was time to weigh anchor and spread the news.

Since that time, it has been called the lover’s knot.