Belief in Jewish tradition

Hello Rabbi,
I hear a lot of your calls and ask for clarification –
The young public today is largely less concerned with the question of whether there is a God; moreover, a large portion of them would agree that there is some kind of force that is responsible for everything around them.
The question that is often asked and that concerns me is – even if there is such a power, how can we know what His will is for us? How do you know that all of the Torah and the commandments as we know them today are truly the divine will for the people of Israel.
Is this a question of trust alone, trust in the great men of Israel, trust in our sages throughout the generations and in the writings that have passed down to us from them, or is there a way for us to draw this conclusion logically on our own?
thanks