Sep 12, 2016, 01:58 PM
Recommend that you grow these berries called the "friendship berries" like the pomeg, kelpsy, qualot, hondrew, grepa, and tomato. These berries are scattered throughout the map/hoenn, though I believe you can get one from the old man (berry master) at route 123. Chances are you likely reset the happiness of a pokemon via trading it over so its value has reset to 70. If you get a steady supply of these berries via growing them, this won't be much of an issues, but it will take time to do so.
