In the literal sense, the term describes a man who is agreeablegentlecompassionatesensitive and vulnerable. When used negatively, a nice guy implies a man who is unassertive or otherwise non-masculine. The opposite of a genuine nice guy is commonly described as a jerk, a term for a mean, selfish and uncaring person. However, the term is also often used sarcastically, particularly in the context of dating,  to describe someone who believes himself to possess genuine nice guy characteristics, even though he actually does not, and who uses acts of friendship and basic social etiquette with the ulterior aim of progressing to a romantic or sexual relationship. There is also a new construct that is arising with the new generation where this is known as the Nice Guy Syndrome. This is when these men who are nice, gentle, and respectful expect that they are entitled to women because they are the nice guy. In their qualitative analysis, Herold and Milhausen  found that women associate different qualities with the nice guy label: Some women offered flattering interpretations of the 'nice guy', characterizing him as committed, caring, and respectful of women.
Able-bodied, it happens to me all the time. This may not be a bite that is entirely unique to the male experience, in which case I hope you can empathize with this very frustrating aspect of dating. Allure is a funny thing. Sometimes it seems to come and go designed for no apparent reason. Believe me, but I could figure it out, I would. Guys experience the same affair. It makes us normal. But we date anyway.