会……的

[Guest123]

I came across a sentence ”你会信守诺言的，对吗？” I understand that it means "You will keep the promise, won't you?"

What I don't understand it's why there is 的. 

If it was "你会信守诺言，对吗？” would it be correct?

 

I've already seen that kind of structure, but I'm not sure if it's often used in books. I mean my impression is that it's rather colloquial.

[xiaokaka]

I think that 的 is used here to emphasize certainty, see

http://resources.allsetlearning.com/chinese/grammar/%22De%22_(modal_particle)

[Chinese.Stu]

Perhaps this is actually the shi...de construction, and shi has been dropped. In some cases, I understand that you can "legally" do this.