For every public address, there is always a Private Key that is paired to it. These private keys gives you full control over the public address, meaning you can send crypto or sign transactions with it. If you have the private key then you basically have ownership of the specific address. And that is why, it is the single most important thing you have to keep safe if you are handling your own funds.
Trust Wallet uses an industry standard for protecting your Private Keys. We are utilizing a 12-word Recovery Phrase for better security and convenience of managing multiple assets. The private key for every coin and token that is supported by the wallet is derived from this Recovery Phrase. As soon as you start creating a wallet, you will be presented by the 12-word Recovery Phrase. So make sure to backup as this will be helpful if you need to restore your wallet.
Create an offline backup of your phrases. Write it down and keep it secure.
If you want to try other options, learn more here: Best Practices for Storing Your Recovery Phrase
Your device has a built in encryption for storing the recovery phrase. However, you can only gain access to the recovery phrase if the device and app is accessible. The Trust Wallet team has no access to your Recovery Phrase. If the recovery phrase is lost, you lose access to your funds as well.