What's the ruling on a person who studies Islam sincerely, but ends up disbelieving?

Suppose a person studies Islam with a sincere heart, but does not find the arguments in favor of Islam genuinely convincing, and dies as a non-Muslim. Does Islam differentiate between such an individual, and someone who denies Islam due to his caprices, or someone who does not even bother studying Islam? Are all three cases the same from the perspective of Islam wrt. their fate in the afterlife, i.e., are they all destined to go hell?