Forex Trading is a decentralized market hence it is neither legal nor illegal , so it is always preferred to do a check before you deposit your funds in any of the brokerage firm.
Loss in trade is should not be our concern, but we should be concerned about security of our funds and transactions.
The First Checklist to Choose the best Forex brokers are following
Regulated /Licences any one of these (IFSC,FCA, Cysec)
Deposit/Withdrawal in same day
Platform(Mt4 Platform or higher version in this)
No additional charges other than spread
Connected with more than 10-15 Lps (for low Spread)
Quick Customer Support.
Different options of mode of payment.
Once that check list is filled you can relax and tell yourself that you have chosen among the best brokerage for your trade.