Both the unofficial and official translations confirm Tarju is male. In chapter 2 when Khalid first gifts Tarju to Ilya, the entire chapter we are told that Tarju is male. Every chapter after that also refers to Tarju as male. The other tiger is female. When the characters asked "Is the tiger male?", they did it out of confusion as to why the tiger was following Tarju's scent, but then they laugh because they realize that the other tiger was more so attracted by Tarju because it's female.
Both the unofficial and official translations confirm Tarju is male. In chapter 2 when Khalid first gifts Tarju to Ilya, the entire chapter we are told that Tarju is male. Every chapter after that also refers to Tarju as male. The other tiger is female. When the characters asked "Is the tiger male?", they did it out of confusion as to why the tiger was following Tarju's scent, but then they laugh because they realize that the other tiger was more so attracted by Tarju because it's female.