Instructions
Capture a Buneary in Eterna Forest. Place the Pokemon in your team. When you catch Buneary, its happiness value will be 140 points. You need to gain 80 happiness points to make Buneary happy enough to evolve into Lopunny.
Navigate to the Key Items pocket of your Bag and ride your bike. Reset the Step Counter and ride your bike until it displays: 20,480 steps. Once you take 20,480 steps with the Buneary in your active party, the Buneary will be happy enough to evolve into Lopunny.
Train your Buneary or give it Rare Candy to make it gain 40 levels. Once it gains 40 levels while in your care, its happiness value will have gone from 140 points to 220 points. For example, if you caught a Buneary at Level 11, it will have enough happiness points to evolve at Level 51.
Feed 40 vitamins to your Buneary. Each vitamin will give your Buneary 2 Happiness Points. At the Veilstone Department Store, one vitamin will cost you 9,800 PokeDollars. You need 392,000 PokeDollars to purchase 40 vitamins.
Give the Buneary a Soothe Bell. The Soothe Bell increases the amount of Happiness Points a Pokemon receives. For example, if you give your Pokemon a massage at the Ribbon Syndicate, the Pokemon will receive 5 happiness points. A Pokemon holding the Soothe Bell, however, will earn 6 happiness points from the massage.