If you have watched Mushoku Tensei closely, you may have noticed that Rudeus is just a normal person like us who used to live their normal days. But he got reincarnated in a different world with a different body but from the inside, he is still a Japanese NEET who is not a fighter or something. On top of it, he always overestimates his opponents and he is just a normal person from the inside. This was the same scenario. Hearing that Gallus is a north saint class sword user and on the top of it, he has a hostage, Rudeus hesitated to fight him.