You can be a confident guy, who's not ugly and does well for himself in school, career, etc. and it doesn't matter if you're a player or not, other people are going to say you are.
It's just like a good looking girl getting called a slut if she laughs at more than one guy's jokes.
I've never considered myself all that, or a player. So you probably wouldn't have crushed on me if I were your age anyway. I've dated actual models, and girls who thought they were models, and I've also dated overweight girls, and plain janes. Usually the latter types were better in a relationship. Trophy girls are a pain in the ass. So are trophy guys.
However, if you don't get to know the guy, how can you tell if he's a player, or if you are making an assumption based on insecurity. Girls get this all the time - the better looking she is, the more extreme the Madonna/whore judgments become. Taylor Swift is a saint even though nearly every track on her albums are breakup songs for different men.
I'd recommend giving a guy the benefit of the doubt. He can be good looking and faithful. Ask these people how they know he cheats. Maybe they see him with girls consecutively instead of concurrently - is he a serial monogamist with a lot of hangup deal breakers?