Sure, guys get rejected. This is exactly the reason why they won't take the effort to beef themselves up psychologically when it's the wrong woman with the right pick-up line. It's cool to be honest right away, though. For example, you'd have to sense whether the girl is single if she has a ring or not on her finger. (Of course, you should know her
pretty name first). If you can't see that, you can ask her right away. The interest you show can be overwhelming. This is spontaneous, and far more convincing than any other.