The best place to buy bitcoins is from localbitcoins and I don't find better and trusted place then it and I frequently buy and sell my coins from the same site and every time the deal is very smooth without any fear of loosing my money.
Every trading site has own security features such as two factor authentication for log in. Automated escrow on completing the trade. Even Polenix, yobit, coinbase are also best place to have the trade. Don't have fear to loose the money. Always check the traders volume and trust ratings to find the good trader.