Here is a strong but polite reply you can use:

“I respect your view, but Jainism is based on Ahimsa, truth, self-discipline, and respect for all living beings. It is not about blind belief or forcing anyone. For me, Jainism is a path of peace, responsibility, and inner purity. You may not agree with it, but I request that you respect it as I respect your beliefs.”

If you want a slightly firmer version, you can say:

“You are free to question Jainism, but please understand it before judging it. Jainism teaches compassion, non-violence, and self-control, which are timeless values. I believe in it with reason and respect, and I expect the same respect in return.”

A shorter version:

“I may respect your opinion, but please respect my faith too. Jainism stands for Ahimsa, truth, and compassion, and I am proud to follow it.”