OK- I'm too lazy to go further down the thread to see if this was answered slightly more completely.
The original game was french. In french (as in other languages) 0 is an egg. An egg is l'oeuf- from which came love.
As to the other scores, fifteen and thirty are one syllable words in french but forty five is quarante-cinq- got shortened to quarante and from there 40.
That's not the story I heard. The original game was English. They thought a player without points could only be motivated by love of the game, hence "love". And as for 40 they originally used 15-30-45-game, assisted in points keeping by a clock. When they figured you should have two points more to win a game, they adjusted 45 to 40, so as to leave room for 50=AD. 40-50-60 is more spaced out than 45-50-60 and should be easier for the umpire.