1) What is the jewish faith based on historical events such as Maamad Har Sinai as stated in the Cuzari or is it only based on a personal relationship with Hashem? 2) If our faith is based on the second example I brought, how can each and every person develope this faith and how does it prove that what we believe in is correct? 3) Is our faith based on something else I did not mention?

Jewish faith is based both on Maamad Har Sinai and on the faith natural to a Jewish neshama. Even if someone accepted the historical truth of Sinai, he would feel it was irrelevant to him were it not for an existential identification with the truths given at Sinai. The existential need would not be in itself sufficient for faith without the conviction in the absolute truth of the revelation and the Torah that we received.