kachpay: "Believe!", imperative of achepay (achuupaayp) "believes, pays close attention to, cares, minds".
kemaaw: "Don't!", imperative of umaaw "is not".
"Does not believe" can also be expressed with verb allyekwii (allychuukwiip), and "don't believe it!" can also be said as, Kallykwi'! or Kallykwih kemaaw!