I can't write a long response but this just simply is not true.
If a guy tries to act "sweet" he will come off as completely unwantable by all women.
If a guy acts like a total asshole then you might get girls, but your love life will be less than satisfying because your relationships will be shallow.
You just have to make yourself hard to get so to speak. Its like pulling a string around a corner for cats. The cat doesnt give a fuck when the string is fully visable. When the string starts going around the corner then the cat gets excited. When the string disappears the cat chases.