In my opinion, coins with potential to increase their value are the safest in the crypto world because it has proven their worth to others which encourage other people to invest on it just like in bitcoin, ethereum, litecoin and XRM.
You must remember that no one is safe in cryptocurrencies, better learn more about cryptocurrencies, and it's better you try with a small capital and don't put all your money in 1 coins.
a little bit of my advice, perhaps you could look at some of the success of ICOs, and you could put your money in that coin.