[He's keeping the flames in his hand but his eyes are trained on Katsa to watch her, making sure things go as smoothly as he hopes (and preparing to stop her in case she accidentally lit a fire herself.) Instead though, much to his relief, it looks as though she's taking his advice and he too sees the lines begin to form again until her palm's glowing just a little brighter the longer she pushed herself.]

Awesome, now you're getting it! It's all about making it into a real thing and keeping your focus. It might take a little while to get really, really good with the fire itself but you just broke through the first hard part.