We know Monergism cannot be true due to the plain fact that to be saved man must repent and believe. Now repentance is forsaking sin/having a change of mind and the word believe is from Greek pisteuo which means to place confidence in; to trust; to be persuaded of. It implies obedience to as a moral choice.
As apeitheo(Believeth not) means refuses to obey, refuse to believe/be persuaded hence.
New American Standard Bible (NASB)
36 He who believes in the Son has eternal life; but he who does not [a]obey the Son will not see life, but the wrath of God abides on him.”