For she has "infallibly" declared she is and will be perpetually infallible whenever she speaks in accordance with her infallibly defined (scope and subject-based) formula, which renders her declaration that she is infallible, to be infallible, as well as all else she accordingly declares, including support for her claim.
While RCs attempt to support traditions of men with Scripture as if the weight of Scriptural substantiation from that was determinative of doctrine, and provided certain assurance of truth, this cannot be the case as that would make them as evangelicals.
Rather, the only authoritative interpretation of Scripture, history or tradition which they may invoke for support is that which Rome gives, and thus the RC's real assurance is based on the premise of Rome's assured infallibility, and their goal is to bring you to cease from objectively seeking to ascertain the veracity of her teachings by Scripture and to trust that in the veracity of Rome for assurance.
Yep, that’s why Loyola can say.
“That we may be altogether of the same mind and in conformity with the Church herself, if she shall have defined anything to be black which to our eyes appears to be white, we ought in like manner to pronounce it to be black.”
VS.
Acts 17:11 Now these Jews were more noble than those in Thessalonica; they received the word with all eagerness, examining the Scriptures daily to see if these things were so.
As I posted earlier today, I believe the corporate-approved phrasing for this is "shut up and kiss the ring".