"Stripe is PCI compliant and your credit card information is sent directly to them"
That sounds as if Stripe is just complying. Doesn't sound trustworthy enough for a company that introduced a far superior method of implementing Payments on websites.
"Stripe is the leader in online payment security. Even we can't see your details"
For non-technical people using physical descriptions they can relate to is more effective than technical terms. Who knows what "PCI compliance" stands for. But everybody knows what a leader is.
Other options to illustrate this effect: Replace "leader" with "pinnacle", "Mt Everest", Nb 1, ...
Same with "sent directly to them". That's a process description. Not a good emotional trigger and definitely nothing that screams secure. It also does not answer the underlying question who can access the information.
"Can't see your details" triggers an emotional response because nobody likes others seeing their details, peeping over their shoulder/ into their home,...
I'm a beginner in copywriting in a UX context and I didn't spend much time coming up with alternatives. If you like to go more into this topic:
I stumbled over two books that opened up my eyes. "Don't think of an Elephant" & "Metaphors we live by".
Written by the creator and leader in the field "Cognitive Linguistic" George Lakoff.
"Don't think of an Elephant" is a political book but it opens up your eyes. "Metaphors we live by" is an academic book that will give you tons of examples on how to choose your words to make your UX more intuitive