In the cryptocurrency industry, nothing is 100% safe.
If you are not in immediate need of your coins and you wish to stake it in the trust wallet, you are free to do so. Whether it's a closed or open source code wallet, I believe it to be secured and it have served the purpose for a long time. So you can safely take your coins and it will be there for you whenever you want them back. Trust wallet is not gonna have issues immediately you stake your coins there.