Your question is very important, and the doubt is natural.

Short, clear answer:

1. At the time of the marriage procession, Neminath Bhagwan did not yet have Keval‑jnan (all‑knowing omniscience).

- He was a Tirthankar‑nam‑karma bearer and a very high‑level soul. - He had extraordinary spiritual qualities and special types of knowledge (like avadhi‑jnan), but Keval‑jnan comes only after diksha and intense sadhana, not during the princely life. - So saying “he had all the gyaans and then felt compassion” is a small misunderstanding. He became Sarvajna (omniscient) only later.

1. Why then did he turn back from the wedding?

- When he heard the cries of the animals kept for slaughter, his natural karuna (compassion) and ahimsa-bhav became fully awakened. - He understood clearly: “If so many jivas are killed for my enjoyment, I become the cause of immense himsa and new bondage of karma.” - This deep inner awakening led him to vairagya (detachment) at once, so he: - Ordered all animals to be freed, and - Sent the marriage procession back, and - Soon after took diksha and later attained Keval‑jnan.

1. But if he already had special knowledge, why did he “ask” about the animals?

Traditional Jain explanations say: - A Tirthankar‑to‑be acts in a human way to teach others. - Many times, they ask questions not because they don’t know, but so that: - The situation becomes clear to everyone around, - The event becomes a powerful updesh (teaching) for the world. - So Neminath’s question to the charioteer is part of this updesh-lila – a compassionate way to make others realize the cruelty hidden in customs like animal slaughter for feasts.

1. Is there any contradiction?

No. In Jain dharma: - Higher the jnan, higher the ahimsa and karuna. - A truly great soul never agrees to happiness built on the suffering of others. - Neminath Bhagwan’s turning back is exactly what we expect from a future Tirthankar: - clear understanding of karma, - complete refusal to be the cause of violence, - and immediate move toward renunciation.

So, Neminath Bhagwan did not “suddenly feel bad despite having all gyaan”; rather:

• His already very pure soul,
• His extraordinary compassion,
• And the direct encounter with suffering beings

all came together at that moment, and he chose the Tirthankar‑marg fully.

You can read more about Neminath Bhagwan’s life and this incident here

A related discussion is also here