hi,,,영원히 can mean forever,,,,but i suggest 늘 meaning "always"
I'll love you forever. 난 너를 영원히 사랑할 거야.
I'll love you forever! 난 당신을 영원히 사랑하겠소!
A thing of beauty is a joy forever. 아름다운 것은 영원한 기쁨이다.
PLEASE COMPARE,,,
늘 meaning "always; usually; habitually; constantly; ceaselessly; continuously; perpetually; eternally; ever; all the time" as in the examples,,,
Promise me you'll always keep in touch. 늘 내게 연락할거라고 약속해.
AND ALSO CAN REFER TO 항상 if u want to,,,,