Who said anything about SELF-assuredness?
Only you.
Filthy Protestants boast only in Christ and what our Lord has promised.
Like Paul did.
I recall Paul injecting into one of his writings, “Where is boasting? It is excluded” ... but not to a works based Catholic or any other cult. If it were not so tragic, it would be amusing how often the cults defend ‘saved by grace, kept by my behaviors’.