Sam took the professor’s response to mean that he would do what be could for Janice. No promise of success, but Sam couldn’t reasonably expect one. He had no plan for what to do once he found his sister, but now at least he had a hope. Or rather, she had a hope, a chance of returning to a normal life. Sam also had hope of being able to meet the professor’s price, for he sensed that Laverty was a compassionate being.