Question: how to evolve eevee in pokemon heartgold?
Answer: Level your Eevee between 4:00 AM and 8:00 PM. After your Eevee has a high friendship level, you will want to battle with your Eevee for it to level at least once. After leveling in the daytime (4:00 AM - 8:00 PM), Eevee will evolve into Espeon.