Complex sentence: Alain has fought at many international events around the world and, after just 3 years in Thailand, was able to able to achieve and become the Southern Champion of Thailand and the World Muay Thai Champion of Thailand.
Split into simpler sentences: Alain has fought at many international events around the world. After 3 years that Alain spent in Thailand, he was able to achieve and win Southern champion of Thailand and World Muay Thai Champion of Thailand.