Dinah grinned right back at her and gave Lian a not-so-discreet thumbs up. She did exactly what she was supposed to do. Sure, her form was a little off but she was five, that was to be expected. She turned her smile to Danny and nodded in thanks for him agreeing to take Lian on... but there was one more thing they should all probably talk about: Lian's mom.
"Lian honey," Dinah started, leaning down with her hands on her knees so she could look at Lian, "If Sensei says it's alright, do you think you can go practice with the other kids for a minute?" Dinah made a scrunched up, disappointed kind of face, "We're gonna talk boring grown-up stuff."
With barely contained excitement, she nodded and turned to Danny to get his permission. If granted, she'd run off to join in line behind Marco and picked up the moves as best she could-- despite the other kids still being a bit awed by her flipping prowess.
With Lian out of earshot, Dinah gave Roy a reassuring look. She couldn't flat out tell him why she trusted Danny and compromise Danny's identity- even to Roy- but she could vouch for him. She wouldn't have brought Lian and Roy here to begin with if she didn't trust Danny... and it was their responsibility to clue him in on what risks he might be taking on by having Lian in his class-- namely the risk that her mother might show up looking for blood. There were other kids to think of that, conceivably, could be caught in the crossfire and Danny needed to be aware of those risks, despite how uncomfortable it might be for Roy to talk about it.
"You should tell him about Lian's mom." Dinah encouraged quietly, touching Roy's elbow lightly and giving him a meaningful look and matching nod. Danny was good people; and it was okay to trust him.