What happens to people who have not heard of Jesus? Will they all go to hell because they are not baptised?

Answer:

The Church teaches that baptism is only essential for the salvation of those who have been told of baptism and who have had the opportunity to decide to be baptised. Because God wills the salvation of all people (cf. 1 Tim 2:4-6), a person who lives according to his conscience and who does God’s will as he recognises it, and who would therefore surely had desired baptism if he had known about its importance, can receive salvation on the basis of this baptism by desire. (Katholischer Erwachsenen-Katechismus, Vol 1: Das Glaubensbekenntnis der Kirche, p. 332)