You already told him during the interview; no need to mention it again. In the Thank-you email, only need to emphasize you and the job are a great match.
"Can you tell me again what’s your maximum pay for this position? " He is not going to do that. You shouldn't have asked.
"I just wish you can pay me that I expected, can negotiation." Grammatically should be: "I hope you can pay me what I expected, but it is negotiable." It is better to write: "As to the salary, I am open for further negotiation." Again, having this in the Thank-you email is extraneous.
"Let me clear know if you give me an offer, totally, how much is your final pay?" When he read this sentence, he wanted to reply as he did right away to rid it out of his system.
Email is inadequate for salary negotiation.
The salary gap may be too wide to bridge anyway. So, don't be too hard on yourself.
