|Ancient Chinese character for Desire|
If you remember the tale of Adam & Eve, the Biblical first man and woman, they could eat from any tree of the Garden of Eden that they wished, except for the tree of the knowledge of good and bad, because they would "positively die". Eve came to covet the fruit of this tree very much, so when the Devil in disguise as a serpent told her she could eat from it, she did. She shared some with Adam, and they brought death into the world, as their bodies slowly began to wither and die.
In the picture there are two trees. In the Bible, it makes mention of two distinct trees of importance within the Garden: the tree of the knowledge of good and bad, and the tree of life. So the inventors of the ancient Chinese characters must have felt that to covet something had much to do with a woman and two trees.