The default is no trust. You shouldn’t trust a random USB stick you pick up in the parking lot, and your customers and users don’t trust you. If you want trust, you have to be transparent in a way your users understand and appreciate.
Somewhere in the Amazon terms & conditions it probably says in illegible legalese that everything you say to your Alexa smart speaker can and will be used against you. Researchers have shown that your interactions with Alexa are reported to dozens of advertisers, and Amazon says the research is flawed. Who do you believe?
Amazon have hundreds of lawyers and are probably within the law. The problem is that they are not complying with users’ expectations. If you want any kind of goodwill from your users and customers, you have to meet their actual expectations. Hiding behind reams of legalese doesn’t cut it.