Can we trust Wickr? I have used it for some communications I would not like to get to wrong hands (but the consequences of getting lost are not too harsh), yet

Can we trust Wickr? I have used it for some communications I would not like to get to wrong hands (but the consequences of getting lost are not too harsh), yet I have roughly zero confidence that the messages aren't stored and that they are delivered end-to-end secure. It's not open source (?) so it can't be audited. The server infrastructure may be wiretapped and/or backdoored by law enforcement together with a gag order. It's headquartered in the US, which I don't trust. They claim to be end-to-end encrypted but how can I tell, let alone the general public who aren't familiar with crypto. I've used Wickr because the other parties I was communicating with were using it. But since I wasn't trusting the other party (cryptography can only assure trust, not create it) so I might have been using smoke signals instead. For my use, it still does beat text messages because at worst it's security by obscurity and my local (non-US) law enforcement can't easily get their hands on the data.