Thank you for your question. In classical theological ruminations, a difference is drawn between those people who have understood the message of Islam and chosen to reject it, and those who don't accept it because they have not understood its message. To further categorize the second group, there is a difference between those who do not know about the truth of Islam because they haven't put the effort to research in order to find the truth and those that have. It is this last group that will not und up in hell according to those ruminations. There is also the issue of those who are mistaken in the path of life they take, perhaps because of a negative interaction with Muslims which has put them off researching Islam and those who are living the message of Islam even if they have not come into appropriate contact with Islam, and these two groups are also given the benefit of the doubt.
So in summary if a person doesn't know properly about Islam, but that is not out of a lack of searching for the truth then they will not end up in hell.
May you always be successful