It means "hi" or "hello." It's pretty much just hey with an O added on the end. I would know, I say that a lot.
Heyo doenst mean I love you it just another word to say hey. Very good question. :)
Possible you mean the Banana Boat Song, made famous by Harry Belafonte?
heyo
heyo
heyo bajenche
heyo captin jack
heyo
Heyo
heyo
hi lol
i love you
Its Korean, meaning "I love you"