If I am asked regarding a fatwá or a ruling and I know the answer (given by the scholars), is it permissible for me to say “I don’t know”, in fear of giving fatwá?

Shaykh Ṣāliḥ al-Fawzān:

If there are scholars whom he can contact, to ask them even if it be by way of telephone or mobile then you should direct him to the scholars, and do not answer him because you might understand it (the fatwá) incorrectly or the fatwá which you transmit may also be incorrect, you don’t know…

Because you cannot distinguish between the incorrect and correct. You may pass an incorrect fatwá or make a mistake when transmitting the fatwá. As long as there are scholars and all praise is due to Allah ﷻ then (you should) direct him to the scholars. If they were in the same country then he should go to them and if not then he should call them.