I Need Your Help Advice Guys Urgent! Potential Sell Of My Life

I'm comfortable with this sub-forum because more honest people are here. and people helped me in here.

Some people know my story in here, some of you guys became my friends, I've been busy lately creating projects and my last website that I created for 1 month I've sell to Flippa for $800 the site have great potential but I need money so I decided to sell it.

I've been buying domain lately for another projects that I can create for a month and then sell it again. Someone emailed me a domain broker and said that his client is interested in my domain. I packaged the 3 domain for $400,000 and if they only want the single domain that they inquire they can acquire it for $200,000 but they are said ok for $400,000 but they need something. I don't know if this is legit. Here it is:

400,000 - Ok.

Before we proceed with the sale my client needs only one thing from you:

My client is an experienced investor and he buys certified domains only to avoid potential risks with trademarks and overpriced/stolen domains. So simple certificates from GoDaddy or Sedo do not suit the needs of my client. He needs a complete certification with a valuation and a trademark infringement verification.

The proper certification contains three points:

1. Independent valuation of the market price. It will show your domain name is not overpriced. On the other hand if the valuation comes higher we will increase the price accordingly.

2. Trademark infringement verification. It proves your domain has no trademark problems.

3. Verification of the owner. It proves you are a legitimate owner and your domain has no any obligations and restrictions. I'm sure that you are a legitimate owner so it will be only a formality.

If your domain has been certified please email me the certificate and we will proceed with the sale. If you don't have the certificate it's not a problem. I may send you a link where you can obtain it. You can read about the certificate agency at Google Answers: Can someone recommend a good appraisal service with a trademark verification? ("Domain Broker" is my nickname).
.
Please don't worry. It takes 1-2 minutes to order it. The results will be sent to you within 24 hours. Then you send me the certificate via email and we'll proceed with the sale As a broker I'm very interested in a good valuation part of this certificate because my client pays me a commission (10-15% of the sale price) on every domain purchase. So I'm not interested in a low price too.

The process is very easy:

1. Go to the certificate agency site and order a certificate. Just submit your domains and let them know you have a buyer with $X,XXX offer and need a valuation near this value. After several hours you will get the results. If the price in your certificate comes higher we will increase our offer accordingly.

2. Then send these results via email and we'll proceed with the deal.

If you are new to the certification process I can help you with the step by step instructions.