Why does it make you sad? Dating/marriage is not as great as it looks from the beginning. Its overpriced by media, movies, tv series and various narratives, even in churches.I feel so terrible. I could never get a girl to like me. Her parents wouldn't approve of me. Her family wouldn't approve of me. Her friends wouldn't approve of me.
I don't believe it will happen for me & that makes me sad.
Being single can make your life much better, much simpler and you much happier than being with a real woman. Men without a relationship/marriage tend to idealize women. But its not that good. If it was, most people would stay together, which is clearly something that is not happening.
Also, her family can be full of terrible people, her friends could be even worse. Maybe you would not approve them. Do not idealize it.