Maybe there are people that even God can't save, but I don't know( ˘•ω•˘ )
know is konw, don't know is don't know
How about listening and accepting what God says about the unsaved and how they will be punished in fire? There is no such thing as not knowing what God will do to those people. God is VERY clear what he will do and he has shown the future to people like John in Revelation.
Rev 14:9 And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,
Rev 14:10 The same shall drink of the wine of the wrath of God, which is poured out without mixture into the cup of his indignation; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb:
Rev 14:11 And the smoke of their torment ascendeth up for ever and ever: and they have no rest day nor night, who worship the beast and his image, and whosoever receiveth the mark of his name.