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It sounds too good to be true.
Literal
Story [subject-が] too-skillful [and so-て] true [definitional-とは] can't-think.
話がうまい ('the deal sounds good') + ~すぎて ('too much, and so...') creates the paradox: the offer is so favorable it arouses suspicion. ~とは思えない ('can't think of it as') uses the potential negative of 思う. A very useful expression for skepticism.