I think this conversation has convinced me that faith does involve trust, where trust is not mere assent. So saving faith is not just mere assent as many Scripturalists have it. It involves what many Reformed believers refer to as "trust."
But on a hunch, I don't think many Scripturalists are going to be very open to this idea until the point that persons are not mere propositions is also contested and demonstrated (as I have done here). When one sees that - that I, a non-propositional reality, assent to certain propositions one of which is that God the Father, another non-propositional reality, justifies or saves me - it follows that I am trusting the Father. As Ron says in that thread, I "rely upon" or depend upon Him.
The point is that in assenting to what the Father says in His word, I implicitly trust or depend on the Father Himself. But since neither He nor I just are propositions, this requires that what mental state the word "trust" corresponds to is something other than mere assent. I can't assent to something non-propositional, at least not in the Scripturalist sense. But clearly I can rely or depend on (trust) something non-propositional.