There is a word that begins with "Z" and means love/loving. That word is Zoriothidist!
zenith is a complementary word that starts with z. It means on the top, or the best.
zanderfide
Zealot
zeal, zealous
zany
Zenith.
zatanous
A word relating to animals is Zoology.
zeal
zoology
Zealous is a word that means the same as happy and starts with a Z.
There isn't a Hebrew word that starts with the letter z and that word means good life. The phrase "good life" is chayim tovim (חיים טובים).