"I'm more interested in how much you'd like to share with me," was Obi-Wan's response.

He'd heard some, discerned some -through the Force- but at the end of the day, so to speak, what was important was what Rey thought about the revelations. For Obi-Wan, it was her impressions that were important and he was hoping that by giving her a relatively blank slate to work from, she would be comfortable in confiding to him.