The initial material must not have been very good, but it had become decent only after a sword cultivator, through prolonged nurturing and refining.
Yu Ziqing did not refuse and accepted the White Sword.
He could tell that aside from being exceptionally skilled in swordsmanship, this fellow was quite average in other areas.
Discussing matters such as killing people without a change in expression or skipped heartbeat, and not even feeling there's anything wrong with that.
With just this fact alone, he was purer than most other sword cultivators.
For most sword cultivators, suggesting that they kill someone would likely feel like an insult to them; they are sword cultivators, not assassins or anything of the sort.
But aren't swords meant for killing?
If you don't want to kill, why practice swordsmanship at all?