Well, Jaskier in the books has blonde hair. He is also actually Geralt’s friend, and they do like each other, unlike the show, where apparently nobody likes anyone else.

He is also quite intelligent, this playboy womanizer who is also just a dummy bard is more or less an act. He is definitely a womanizer, but he’s also a respected scholar at Oxenfurt, where he aced his final exams and got a job as a professor despite his opinion as a lazy drunkard, which he cultivated during the time he was a student there. Oh and he’s a spy for Dijskra.