Women in general have a hard time saying "no". They say maybe, or probably not, they get coy and say "maybe later" or "another time, perhaps", or "I don't think so". Another woman gets it. A man doesn't. He hears "probably not' and translates that into "maybe". He hears "I don't think so" and hears the uncertainty and not the emphasis.
Men and women interpret the language differently, in much the same way they percieve colors differently. There is an old cartoon in which the lady of the house says to the painter, "I want this room to be painted a nice robin's egg blue, but not too much green in it, just a hint, and a warm cast to the blue, and for the bedroom, a nice warm cream with just a bit of pink in it". He turns to his assistant and says, "blue for the living room, white for the bedroom."
Older women especially learned or were taught that an outright "no" is harsh, masculine, and rude. This is a hard lesson to unlearn, and yes, it's hard to learn how to say such a simple word without qualifiers, without sounding like a shrew, without looking as if you are about to have a tantrum. I learned the trick by magic, one night when I was tired and weary of the arguing at a meeting, and was given a job to do that I hadn't asked for and knew I would do poorly. I no longer cared. So I just said "no". No qualifying "No, I really can't" or "no, I don't think I could do a very good job at this" (both of which open the door to argument). "no", she said. Silence.
Someone else got the job and I was off the hook.
Afterwards I thought, what just happened here? No one argued, no one asked why. It was amazingly freeing. And it isnt rude at all. Hell, men do it all the time and no one tells THEM it's rude...