Work colleague wanting to set me up with her brother

[petal28]

As the title says, a work colleague has offered to set me up with her brother as this colleague has heard from another colleague that i'm "on the market and looking". Only thing is i don't want to be set up with her brother because i would like to settle down with a man who is from the same culture as myself (colleague's brother is not). I'm not sure what i should say to my colleague to let her know that i don't want to be set up but not offend her. I'm also worried that my colleague might hold it against me as i will be applying for a work promotion later on and the colleague might have something to do with that process. How can i let my colleague know in a diplomatic way (without lying) that i'm not interested?

[fltc]

"I would like to settle down with a man who is from the same culture as myself" is what you need to tell her.