You speak of confidence. If a very confident male approaches a female, it can be overwhelming. He comes on strong, so she needs to step back to assess what he's all about. If he continues to be overwhelming, it can be hard to read so we tend to let that one go. However, if she sees him at a distance, talking to another woman, very relaxed, lots of smiles and laughing, that gives a feeling that he's fun, nice, easy to talk to. Approachable. She can get a read on him before they ever interact.
It also depends on the environment. Is this beach activity?