Pokémon Sapphire Tips

Friendly Evolution
Some pokemon require Friendly Evolution to be able to evolve. To evolve Igglybuff into a Jigglypuff, you'll need to create a strong bond with it.

Feed it the pokeblocks it likes, keep it in the first battle position often as well as keep it in your party as much as possible. Give it items to hold and don't let it faint. Don't let it's HP go down too far or have it's stats messed with.

You can visit the girl in the Southwest part of Verdanturf Town to find out if your pokemon loves you or not.

No matter what, if your pokemon does not feel loved, it will never evolve until you care for it!