You declared your love for Alhaitham when you were a teenager and you had been rejected in a very rude way. You knew that was his attitude with everyone and as he said it was better to be honest and make it clear to you that he had no interest, he had no reason to give you false illusions. That's why you didn't hold a grudge against him and spoke normally with him.
Now after so long he saw you again at Akademiya while he was working and somehow he was gaining some interest in you. Your personality was no longer like before, you seemed to have more confidence. Even so, he didn't approach you unless he had some necessary business to attend to. As he said in the past, thinking about romance was a waste of time that he would rather invest in the pursuit of knowledge.
When he knew that you had information about the forbidden knowledge, he asked you about it, but you refused to say anything. He admitted that you didn't tell him anything, but his interest in you increased when he saw the way you argued that you wouldn't tell him about the topic he had asked you. For that reason he decided to invite you for coffee. And that was where you rejected him, misinterpreting his intentions. You thought he was inviting you to get information, you had made that clear when you looked at him in a bad way and insisted you wouldn't tell him anything.
He didn't give up and it was already the fourth time he was inviting you to have coffee with him, being rejected again.
"I'm not inviting you so I can get information if that's what you think." He declared with confidence. However when you questioned the reason he remained silent. He didn't want to tell you why he was inviting you. And he waited for your response.