A lot of people on TRP think you can't be TRP and still be a Nice Guy at all.
I've had numerous people, my wife included, tell me that I'm one of the nicest people they've ever met. I was told that in high school, I was told that in the Marine Corps. I've been told that in numerous jobs.
But there's two things I would point out. First, is that I've always considered being nice to be kind of a worthless trait. Like when someone says "hey what do you think of old generic name over there" and they say "oh... he's a nice guy", that's basically their way of saying "I can't think of anything positive to say about them, so I'll define them as nice". And so when you call someone " a nice guy" you're basically saying "I don't hate that person, but they really don't have any redeeming qualities so I'll call them nice". And what you end up getting is a whole lot of people that are really just not that nice being called nice, because they're not complete shit bags but they've got nothing else going on.
When I was in the Marines and one of my lieutenants said I was a nice guy it was after a very positive performance review. He said that I was very respectful of the Marines under me (I was a Sergeant at the time) and in turn they respected me. And he joked that the rare times when I did start yelling people were not used to it and I got quick compliance. I was never called an asshole for getting people in line because in general my style was not being an asshole.
Same with my wife. When we met she didn't want to give me the time of day because I was a Marine. She said she thought I was good looking and in awesome shape, but that Marines are all assholes. But after getting to know me a bit she changed her mind, and here we are over a decade later. But it's the same thing - I'm kind to her, her family likes me, and I'm successful at providing for our family. And I'm pretty sure she still finds me attractive. I try to be slow to anger. But being a former Marine I won't stand for disrespect and I won't hold back when it's needed. And again, I don't remember her ever calling me an asshole because when I do speak my mind she respects me and my opinion because my worth to her is not built on 'being nice'.
I find being an asshole, when using that term as described above, is exactly what a woman wants. It means she respects you but is frustrated that she can't manipulate you.
Now that I'm rereading your post, I think I'm getting at the same thing you are. Maybe I'm just fortunate enough to have a wife that doesn't try to manipulate me, who knows.