Here's why:
* Veela charms primarily affect men: While Veela are beautiful creatures with powerful charms, their magic is specifically designed to be irresistible to men.
* Ron is not particularly susceptible to charms: Ron is not known for being easily swayed by appearances or magical influences. He is more grounded and practical than many other characters, making him less likely to be affected by charms.
* Ron's relationship with Hermione: Ron's love and loyalty to Hermione would likely counteract any charms Fleur might unknowingly cast. He is deeply in love with Hermione and his affections for her are genuine.
Therefore, Ron's reaction to Fleur in Deathly Hallows is more likely to be based on his personal opinions and experiences, rather than any enchantment.