In Ling Han's previous fight with Xianyu Ziyuan, Xianyu Ziyuan's martial intent entered his body in the end, and he resisted against it for one entire month before wearing it away.
This allowed him to touch a slight edge of Sword Heart, but this last step could take several days to cross, or several years, several tens of years, several hundreds of years, or even remain unaccomplished in his entire lifetime.
The comprehension of dao was just that mysterious. The saying: to cover ninety percent of one's destined distance brought the traveler no farther than the midway point meant that before succeeding, it was no different from treading in the same place.