It would seem that how much at peace a man is with himself is not a necessary test of whether he possesses spiritual wisdom, since many saints in Christendom knew little peace within them (but trusted God nevertheless).
I respond, using St. Augustine's definition of peace as "the tranquility of order," we start by noting that wisdom (of the kind that comes from above, which is the only kind we're considering here) is right judgment in light of the Divine Will. To be wise is to know things as they are, and to act accordingly.
Now, to act according to the way things are is to accord each thing its proper place. In other words, it is to act so as to bring about, restore, or preserve the "order" in St. Augustine's definition of peace. It is, as I suggested before, almost literally to make peace.
There's no denying that a saint who trusts God is a peacemaker in this sense, acting to bring about, restore, or preserve the order willed by God both within his heart and between himself and others. What I guess is denied is that acting to create this order necessarily results in tranquility. Ordermakers, so to speak, aren't necessarily peacemakers; in fact, merely acting with wisdom may even fail to result in order, much less peace.
To take the last argument first, acting with wisdom does necessarily result in order: specifically, the order within one's will by which the wise thing is done and the foolish thing avoided. True, this isn't the only order the wise man seeks, but it is virtuous in itself and apart from any question of the success of his actions.
If acting with wisdom necessarily creates an order of some sort, does this order necessarily create a tranquility of some sort?
man's heart is not at peace, so long as he has not what he wants, or if, having what he wants, there still remains something for him to want, and which he cannot have at the same time.
Tranquility, then, can be understood as the absence of contradictory desires. (This tranquility is true peace when the complimentary desires are all ordered to the Eternal Law.)
So the question can be rephrased: If someone acts with wisdom, is he in some way necessarily free of contradictory desires?
I'll tentatively say yes in a limited sense, and no in a more general sense.
Consider Jesus in agony in Gethsemane. Was His heart at peace? I think most of us would say no. People at peace don't sweat blood. St. Matthew writes that He felt "sorrow and distress." He could not do the Father's will and have the cup passed Him by at the same time.
In a narrow sense, though, there was a kind peace in His heart. "Abba, Father, all things are possible to you. Take this cup away from me, but not what I will but what you will." His desires were ordered to the Father's will, so much so that the desire to be spared -- which superficially conflicts with the desire to do the Father's will -- was actually conditional. His desire wasn't simply "to be spared," but "to be spared if the Father willed it."
From this perspective, then, even in His agony Jesus did not have contradictory desires, and in this sense He had peace in His heart. Not a very satisfying peace, from a natural perspective, but then, as He says in the Gospel of John (which, of course, does not record the Agony), "my peace I give to you. Not as the world gives do I give it to you."
Perhaps this peace of God -- which, as you know, surpasses understanding -- isn't so easy to detect in another's heart, after all. (Or maybe it takes a saint to know a saint.)
Still, Jesus immediately adds, "Do not let your hearts be troubled or afraid." The gift of heavenly wisdom does seem to guarantee a certain spot of peace, even in an otherwise roiled heart, just as it does in an otherwise roiled world.