Question: how to quickly evolve eevee into espeon in heartgold?
Answer: After having a full friendship meter and leveling during the day, Eevee will evolve into Espeon. You can achieve this by battling with your Eevee on the team (without it fainting), keeping your Eevee on the team, giving it berries and protein, as well as giving it haircuts and taking it to the National Park.