Once upon a time, there was a, semi barbaric, King with a daughter who he loved very much. He held this trial for the criminals in the kingdom. In this trial the people would have to chose between a door with a tiger behind it ready to eat them or the door with a women that they had to marry them.
The princess and a lowly commoner had fallen in love. The King was unaware of it and was not happy. So he put the commoner in one of his trials and he would have to chose which door.
The princess knew what was behind each door. So she had to decide if she would watch him be happy with another girl. Or to just kill him so she doesnt have to see him happy with another girl. She knew she would lose him either way.
The Princess finally decided what she would. She signaled to the right.
The commoner had to decide which door. The door with death or the door with rejoicing and happiness. Then wondering what the Princess had signaled.
Finally, he opened the door and the tiger came out. The Princess thought that it would be better for him to be gone to death then to have to live knowing he was married to another women and was happy. Her jealousy overpowered her love.