Resolved questions
How to write this in Korean

assuming the other person is a friend...

1. Hi XXX, Happy birthday. I know it's late, i am very very sorry.
-> 안녕 xxx, 생일축하해. 축하가 늦어서 정말 미안.

2. I know you're a very kind person, so i wanted you to meet someone who's very kind as well.
-> 넌 굉장히 친절한 사람이니까 난 니가 너처럼 아주 친절한 사람을 만났으면 좋겠어.

3. Please accept this book as your birthday present.
-> 생일선물로 이 책을 받아줘 (생일선물로 이책을 줄께)

4. I hope you'll enjoy it and have a happy and peaceful life.
-> 니가 그걸 좋아했으면 좋겠어. 행복하고 평안한 날이 되길 바랄께.