To address the challenges associated with shape sensing of continuum manipulators (CMs) using Fiber Bragg Grating (FBG) optical fibers, we feature a unique shape sensing assembly utilizing solely a single Optical Frequency Domain Reflectometry (OFDR) fiber attached to a flat nitinol wire (NiTi). Integrating this easy-to-manufacture unique sensor with a long and soft CM with 170 mm length, we performed different experiments to evaluate its shape reconstruction ability. Results demonstrate phenomenal shape reconstruction accuracy for both C-shape (< 2 mm tip error, < 1.2 mm shape error) and J-shape (< 3.4 mm tip error, < 2.3 mm shape error) experiments.