[ He looks incredibly pleased by the offer. ]

My world has no magic to speak of, so I would like to know everything you can tell me.

[ He does mean everything. He listens, considering, and as he hasn't had the discussion with Xue Yang about his sword yet he doesn't actually know much about these golden cores. ]

Stronger and faster in battle? That sounds incredibly useful, and even better if you can't get wounded. How long is your life span then?