Based on the level of respect or formality, you can say "You are a luncky person" in Korean in 3 ways:

• Informal: neo-neun haeng-un-a-ya (너는 행운아야)
• Formal: dangsin-eun haeng-un-a-yeyo (당신은 행운아예요), dangsin-eun haeng-un-a-ipnida (당신은 행운아입니다)
• Very Formal: dangsin-ggeseo-neun haeng-un-a-isipnida (당신께서는 행운아이십니다)

- you (subjective): ne-ga (네가), ni-ga (니가), neo-neun (너는), dangsin-eun (당신은), dansin-ggeseo-neun (당신께서는)
- lucky: haeng-un-eui (행운의)
- luck: haeng-un (행운)
- person: a (아), saram (사람)
- lucky person: haeng-un-a (행운아)

Please refer to How to pronounce Korean Alphabet for the English pronunciation in this answer.