The most romantic words is "PoPo-HaeJo" It means KISS ME!! lol
You should know It is most effective words of girl for killing guys~ -x- kk

romantic in korean is romantic too
sorry can i know u? i am kosa i live at cambodia i study korean too

me too i wish learn korean l

This is a longer one - I'm not sure if it's romantic or too strong but you can try. ^^

내가(I) 어떤(what kind of) 삶을(life) 살게(will live) 될지 모르겠지만(don't know but)
nae-ga oh-ddohn sal-ge dwil-ji mo-reu-get-ji-man
I don't know what kind of life I will live but,

나는(I) 언제나(always) 당신(you) 곁에(with/next to) 있을게(will be).
na-neun on-je-na dang-sin gyoh-te de-sseul-ge
I will be always with you.