Not really sure, but their developer page claims that the wallet is open-source[1]. If it's accurate, then it's definitely a positive thing.
On the other hand, regardless if it's safe or not, it's really not recommended to hold huge amounts on money through a software wallet. 99% of people should always go with reputable hardware wallets.
[1]
https://trustwallet.com/developer/I can see that on
GitHub and the code is often updated, but that should not be a reason yet that it is open source. Or you check the codes and completely verify that they are completely open source? I am not a developer and I can not verify this yet. Let us see other members that know about this to comment before we can decide it to be completely open source.