Webster's Revised Unabridged Dictionary · 1913

Trow

Trow , noun

A boat with an open well amidships. It is used in spearing fish. — Knight

Trow , verb, intransitive and transitive

[Old English trowen, Anglo-Saxon treówan to trust, believe, from treów trust, treówe true, faithful. See True.]

To believe; to trust; to think or suppose. [Archaic]
So that ye trow in Christ, and you baptize. — Chaucer
A better priest, I trow, there nowhere none is. — Chaucer
It never yet was worn, I trow. — Tennyson
What tempest, I trow, threw this whale... ashore? — Shakespeare
What is the matter, trow? — Shakespeare

I trow, or trow alone, was formerly sometimes added to questions to express contemptuous or indignant surprise.