Complex sentence: Her body is buried in the Prince's Army Castle, since many people didn't know her true motives and think of her a traitor unworthy of being buried on the Royal Cemetery of the Sun Palace in Sol-Falena.
Split into simpler sentences: Her body is buried in the Prince's Army Castle. Regardless of her true motives, the fact that she betrayed the Prince prevented her from being buried in the Royal Cemetery of the Sun Palace in Sol-Falena.