"I can do that." That look remained in her eyes but she smiled a little as she nodded. "Ask Harry. My veils are the best. Better than his. Even using the Sight wouldn't help much unless they knew what they were looking for, but I don't stay in one place long enough to let that happen."
She winked at Jo then started moving through the crowd again. "I'm used to working on my own now. I had to after Harry..went away for a while." That's the only way Molly could think to put it without wanting to get into the lengthy explanation of dead Harry then not dead Harry. "But I wouldn't leave you behind regardless of how it looked. I make pretty convincing illusions so don't let them fool you."
It was a show of trust that Molly was giving Jo some of her best secrets and tricks. If she really thought Jo was someone who would turn on her she wouldn't have told her the last bit.