Based on the level of respect or formality, you can say "I like hwa rang do" in Korean in 3 ways:

• Informal: na-neun hwarangdo-reul joahae (나는 화랑도를 좋아해)
• Formal: na-neun hwarangdo-reul joahaeyo (나는 화랑도를 좋아해요)
• Very formal: jeo-neun hwarangdo-reul joahamnida (저는 화랑도를 좋아합니다)