How do you know what is valid/correct/';true'; knowledge of what is and what is not?

I think she is asking how do u know what is true and what isnt and whats important to u in determining truth?How do you know what is valid/correct/';true'; knowledge of what is and what is not?
She may be asking what the differences are between those, because there are differences. All logicians cringe at the thought of people thinking that arguments can be 'true' or false'--they can't. Arguments are only valid or invalid, that is to say, the conclusion of the arguments follow from the premises--that's all validity is describing. IF the premises are true, and the argument is valid then the entirety of the argument is said to be 'sound'. An argument that is sound is said to be necessarily true, i.e. impossible to be false. This may be what 'she' means by correct.How do you know what is valid/correct/';true'; knowledge of what is and what is not?
All we can do is use our common sense and education to see if it sounds right. Often we are wrong, that;s all there is to it.
truth is as hard to define as reality i think. How can you really be sure of anything? I think its just faith in what you believe to be true, what you believe to be real.
True knowledge harmonize, connects and unites, it benefits everyone. False knowledge would do the opposite.