Same as Taron Malicos, Trilla isn’t an easy battle but she hasn’t got as many attacks up her sleeve. In order to deal damage to Trilla you’ll want to slowly break away her Stamina bar by countering her attacks and then going in for a couple of hits when it’s empty. Whilst taking away her Stamina bar, she may glow red and grab Cal to throw him on the floor before taking a swing with her Lightsaber, if you see this make sure to get away quickly.
Another Red Attack she can perform is to simply dart forward to attempt to get you with the end of her saber. If you find yourself with a large gap between you and her she’ll dash towards you and then quickly do a spin attack which can be painful if you were to get trapped in it.