πίστις, ἡ, gen. εως: dat. πίστει, Ion. πίστῑ: Ion. nom. and acc. pl. πίστῑς; dat. πίστισι: (πείθομαι

:
pistis—
trust in others, faith, Lat. fides, fiducia, Hes., Theogn., Att.; c. gen. pers. faith or belief in one, Eur.:—generally,
persuasion of a thing, confidence, assurance, Pind., Att.
2.
good faith, trustworthiness, faithfulness, honesty, Lat. fides, Theogn., Hdt., Att.
3. in a commercial sense,
credit, trust, πίστις τοσούτων χρημάτων ἐστί μοι παρά τινι I have credit for so much money with him, Dem.; εἰς πίστιν διδόναι τί τινι Id.
4. in Theol.
faith, belief, as opp. to sight and knowledge, N.T.
II. that which gives confidence: hence,
1.
an assurance, pledge of good faith, warrant, guarantee, Soph., Eur.; πίστιν καὶ ὅρκια ποιεῖσθαι to make a treaty by exchange of assurances and oaths, Hdt.; οὔτε π. οὔθʼ ὅρκος μένει Ar.; πίστιν διδόναι to give assurances, Hdt.; διδόναι καὶ λαμβάνειν to interchange them, Xen.:—of an oath, θεῶν πίστεις ὀμνύναι Thuc.; πίστιν ἐπιτιθέναι or προστιθέναι τινί Dem.:—φόβων π. an assurance against fears, Eur.
2.
a means of persuasion, an argument, proof, such as used by orators, Plat., etc.
Liddell, H. (1996). A lexicon: Abridged from Liddell and Scott’s Greek-English lexicon (641). Oak Harbor, WA: Logos Research Systems, Inc.
God gave us the assurance based on his promise and his work. But it does not guarantee we will be assured of What God offers us.
Not to mention. No where does it say this only comes if God allows it, or it can only come from God. we can have PISTIS in things not related to God.