What is meant by the disbelievers hearing about the Prophet and entering Hellfire if they do not believe: Is it merely hearing, or is it sufficient knowledge for belief?

The meaning of hearing about the Prophet (peace be upon him) in the hadith "No one from this nation, neither a Jew nor a Christian, hears about me, then dies without believing in that with which I was sent, but he will be among the people of the Fire" is to know of his message and for the news of his prophethood to reach the servant. So, whoever receives this news is obliged to research the proofs of his truthfulness and believe in him. Scholars have differed regarding those to whom the call did not reach in its proper form. Some of them hold that such a person is excused and will be tested on the Day of Judgment, while others hold that merely hearing the news of his prophethood obliges research and belief, and whoever falls short in this regard is blameworthy and punishable.