The study reported here is the third in a series of research articles (Harkness, S. S., D'Ambrosio, B., & Morrone, A. S., in "Educational Studies in Mathematics" 65:235-254, 2007; Morrone, A. S., Harkness, S. S., D'Ambrosio, B., & Caulfield, R. in "Educational Studies in Mathematics" 56:19-38, 2004) about the teaching practices of the same university professor and the mathematics course, "Problem Solving," she taught for preservice elementary teachers. The preservice teachers in "Problem Solving" reported that they were motivated and that Sheila made learning goals salient. For the present study, additional data were collected and analyzed within a qualitative methodology and emergent conceptual framework, not within a motivation goal theory framework as in the two previous studies. This paper explores how Sheila's "trying to believe," rather than a focus on "doubting" (Elbow, P., "Embracing contraries," Oxford University Press, New York, 1986), played out in her practice and the implications it had for both classroom conversations about mathematics and her own mathematical thinking.