It is very clear that Quran forbids intercourse between man and woman before marriage.
However, when it comes to relationships, the only close reference I have from Qu'ran is that we should "lower our gaze and guard our sexual organ", but so far I didn't see any direct forbiddence in being in a relationship with a girl which does not involve any haram interactions.
There are many many rulings on dating and relationships by various people, fatwās, and scholars, such as this. But very little citation is directly from Quran. I want to say that I trust only in Allah and his Angels, the Holy Quran, and Prophet Muhammad, but not in any other worldly people when it comes to how to live my life.
So my question is, is there any direction citation from the Holy Quran, or Prophet Muhammad (but no more than these two) that talks explicitly about:
1) What are haram interactions apart from anything to do with sexual organs according to Quran? (Such as, kissing, holding hands, cuddling, meeting in private etc)
2) Forbidding relationship between men and women which does not involve any haram interactions before marriage.