I didn't really mean it
However, there's an explanation for what they're saying. Soi Fong became who she is mostly because she idolized Yoruichi, and even up to now she maintains a pretentious air. Being an assassin was her job, not her psyche. So, in that sense, it's possible that her real personality is something related to her bankai and not to her being an assassin. I think it's unlikely, though.
Instead of, "Steve works for the City's police force as a cop. But Steve doesn't act like a cop.
Soifon is an assassin as she has been trained and fully mastered that arts. But the way she idolizes Yorichi (or however you spell it) gets in the way of her assassin character.
It's too strong, it won't fit
It's too much, it's too tough
She talk like this 'cause she can back it up
She got a big bankai, such a huge bankai
I love her big bankai, it's too much
She walk like this 'causes he can back it up
Bankai so big, you must admit
I got every reason to feel like I'm that bitch
Bankai so strong, if you ain't know
I don't need no beat, I can sing it with piano
Man that sounds gay :(
I'd say it's an even greater accomplishment that she's managed to become a master assassin considering her personality traits, never mind the fact that she apparently completes her missions without ever having to release her bankai, or at the most, very rarely.
"For I being a poor man, have only my dreams & I have spread them beneath your feet. Tread carefully, for you tread upon my dreams."