He wasn't used to her silence. Silence from Trouble could be, well, trouble. Normally her silence meant that she was planning something, so to say that he was a little nervous about her reaction was be an accurate description. He stood awkwardly, waiting on her to make a move. When she mentioned the price and asked if he was sure, he nodded.
To prove that he was dead serious he moved to stand behind her and gently put the necklace around her neck and did the clasp. "I'm positive. It doesn't matter how much it cost. I saw it and it reminded me of you, so I want you to have it," he said, letting her hair fall back down into place once he had had made sure that the clasp was done correctly.