다행히 (tahaenghi) means “fortunately”

More examples

다행히도 비가 오기 전에 도착했어요.ta haeng hi do pi ga o gi cheo ne to cha kae sseo yo

Fortunately, I arrived before it rained.

A better-than-expected result brings relief and gratitude.

다행히도tahaenghido: Fortunately, things work out well in the end.
운 좋게도un chokedo: Luckily, chance helps produce a favorable outcome.

예상보다 결과가 좋아서 안심하거나 감사의 뜻을 전할 때 쓰는 부사ye sang bo da kyeol gwa ga cho a seo an sim ha geo na kam sa ui tteu seul cheon hal ttae sseu neun pu sa

Its base expresses good fortune, and an adverb-forming suffix turns it into an adverb meaning fortunately.

It usually appears inside a sentence before the fortunate outcome, so it works like fortunately rather than as a standalone reaction.