Types of sentences

I know that there are 4 types of sentences.

Assertive
Interogative
Imperative
Exclamatory

I want to learn a little more about the rules that these sentences follow. Actually I recently i asked a question about

the usage of auxiliary dare and main verb dare and i got the folowing answer.

There is no requirement in those sentences to use either one or the other form of dare.
You are free to choose whichever you like, because both are in non-assertive clauses (questions, negatives, or hypotheticals in form or meaning).

If you dare breathe a word / If you dare to breathe a word

None dare speak freely / None dares to speak freely

The assertive form almost always occurs with the full verb.

He dares to speak up in class (and so do I).

*He dare speak up in class (and so dare I).

And now i don't know what does the replier meant by "both are non assertive sentences". I don't have any idea about what

rules each one of the types of sentences follow. So i think i need some basic indepth grammar information to understand

the fundementals of grammar. Please if someone can help me with such basic rules (but in depth) send me some links to the

source or send a post.

Thank You.