Charlie listened to him, understanding wanting to go back. It wasn't just their home but Splinter they were missing greatly. No one could blame them for that. Charlie herself missed her own father especially after just leaving him a few days after the mutation. She just wished she could have explained to him. 

She was brought out of her thoughts upon hearing him question about her promise. "Of course I did. I never go back on a promise." She replied before gently placing a hand on top of his. "I can't explain it, but I feel like he's still alive. He's out there, probably with the Foot. All we have to do is get one of those goons to tell us where he's located." 

She gave him a little smile. "The last thing we all need to lose is hope. Without it, what else is going to bring us back to the city?"