Knowing the witness of the HG ain't rocket science, but it is obvious why some here are having difficulty.
For example:
3 Nephi 11:29 and 2 Tomothy 2:24
and
D&C 6:15 and D&C 8:2
For those that would argue that a person may be "fooled by" or "misunderstanding" when the HG has witnessed to a person, i would say, plainly, that they do not understand because the simple requirements for confirmation. Is a person 100% accurate with recognizing the HG? i would say not, but there is not one here who can deny ever uttering the words, aloud or to themselves, "something told me that would happen....." - or - "I had a feeling that was it..." ; especially when their conscious mind had chosen to do otherwise.
This amateur rebuttal of "explain to me how you know it is the HG" is absurd and childish and unsupported by any rational means.
Simple example for the naysayers.....

is the above statement true or false by your reasoning?