No, Any guy I know who girls consider to be attractive know it... I actually don't think any of them have really been rejected. I think it's funny how most girls I know say they aren't shallow then completely pine over a guy they don't know because they think he's good looking. Even if they were to be rejected they probably just shrug it off, I mean I know a guy who girls seem to be attracted to and he might have a thing with them before they won't take it any further... but he just moves back to another girl or finds a new one. I'd consider myself unattractive or average at best, and I have absolutely no confidence compared to 'attractive guys'. Put it this way, attractive guys are often cocky because they know girls are often attracted to them. I feel like girls will reject me because I'm not attractive/many girls don't find me attractive so I don't believe I'll have a shot.
It can go either way. I constantly read girls saying that good looking guys are very cocky. Some girls will even judge a guy just for wearing a tank top.
I would say honestly that average looking guys are probably more insecure but hide it very well. If a good looking guy came up to their girlfriend they'd probably be terrified but not admit it. I honestly see "average looking guys" more resentful to women in general constantly posting topics here about how they are too scared to approach women.
As for good looking guys I think they'd probably brush off a rejection and just compensate it mentally with something silly like "She turned me down because I'm so good" or some garbage. But I could also see a good looking guy being like "How the hell could she reject me!? I look so amazing!"
No not true. Guys who are confident are usually never lacking in the looks and/or money department and they always get validation on their looks from women so having confidence is easy when your looks are accepted.