My style is flirt style (My CHA is 11). So, I flirt him a lot until I win them
Up to your style . My style has weakness against immune flirt foe. You can upgrade your weapon ( I also did it) to reach maximum upgrade of your weapon . When you fight with Selye try to combine Bind up skill with MP potion. Bind up skill is heal you more than HP potion. When you see left topscreen use defense.