Men in this world were much more reserved with their emotions, and a nobleman would be even more inclined to keeping his feelings in check. He would have learned to do so from quite a young age.
If she were to compare the traditions she had grown accustomed to with those from her world, it would be more similar to the customs of ancient times. Furthermore, as aspiring cultivators, men in the sect were often raised to consider romantic feelings a hurdle or something to be suppressed, not something to pursue. It would be rare for a lover or a husband to profess his affections to his beloved, if the action was not nonexistent.
In this regard, Zhu Qingyue's avoidance of the opportunity to confess his feelings was not entirely out of the norm.