1) If you want to refer to someone who has not had his or her first sexual experience, then "virgin" is an ordinary noun. It's hardly romantic to me. If you wanted a more poetic word, pure, innocent, unsullied... those are a few choices.
2) I'm sorry, you need to ask someone with a more poetic heart than mine.
3) It means you are making a promise, or swearing that something is true.
I'll be there promptly at 8. I promise. Cross my heart.
No, really, I swear - Jim really said that. Cross my heart.
Fleur de mortGuest