The best and the safest way to sell your bitcoins is to be a part of trusted and reputed site and it will also depend on the country that you are living in as for me localbitcoins is the best place to sell my coins.
I agree with you that there is many trusted sites for buy and sell bitcoin and you are right localbitcoins is much more better than other and i also buy and sell my bitcoin through localbitcoins and i feel safe in localbitcoins.
If you are transacting with a legitimate company you feel better and for me that is a safe way to sell, I have been doing continuous transaction with my local exchange and I can easily buy and sell, what I am doing is safer than looking for someone who can sell you bitcoins and buy your bitcoins.