Ben didn't need to tell Finn about Rey's history. What she had to go through. How alone she had been for so long, stuck on Jakku waiting for a family that would never come. He'd seen all that despair and lonliness in her mind. The longing to be part of a family once again had been so strong. He hadn't needed to push far into her mind to see that. She had taken on the BB unit and Finn so quickly, like she had been waiting for them all along. How funny that she had been able to bond with Han so quickly. But Ben understood where Finn was coming from too.
"Time, is what I've learned. It'll just take time. But I don't know if I'd take any advice from me about this. I'm not exactly known for my patience." Finn was already aware of that. Stories of Kylo Ren's violent temper and outbursts were carried through the First Order worse than gossip.
He looked down to Finn's hand. There was a moment of hesitation as if he expected it to be a trap. Ben looked up to the other man's face. His eyes narrowed like he was about to try and read his mind but then he thrust his hand out and took Finn's firmly. After a brief shake, he let go. "Sorry about your shirt. I'll get you a new one."