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

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