ParaAduma

Some Niddah questions:

Is a woman required to do a bedika on her levainim each time during her shiva nekiim?

Is there a situation where a woman can declare she is a Niddah (when she really isn’t) and still be considered tahor?

There is a case discussed about a woman who goes to the mikvah without daas to be tovel. How can such a case exist if she must do a verified good chafifa beforehand?