You have taken a better step by considering the security of an unknown and new website before submitting your personal information. Some spam websites collect your personal data and use it for unsocial activities. Now I think you are talking about online money making websites. If your answer is yes, it is very easy to know the genuineness of any website. There are several thousands of money making sites like Paisalive, Clicksense, dollarsincome, probux, PTC box etc. Out of them 99.9 percent are fake i.e. if your target is to make 4100, you may have to work for at least one year or even more. Yes, to check the genuineness of one such website I worked for one month but, I've earned just $0.80 by working daily. So, I wasted one month and got nothing except wastage of around 50 hours.
So, remember one thing that no one in this world gives you dollars for free. Coming to the safety of a website, you can check it based on users reviews. If you Google for reviews of any such new website you found you can have lots of reviews on it. Also I suggest you to check their safety using websites like 'scamadviser.' These websites displays the safety level of a website and the reputation of it among the users.
There is another such tool called 'web of trust' which is a Google Chrome extension that warns you when you are about to enter a malicious website. This WOT shortcut for Web Of Trust completely functions on users reviews and ratings. If you find any vulnerable website, you can report and rate it in WOT's score card. This makes the next visitors browsing more safer and secure. I hope you have understood how to detect the safety of a new website.