1) Diffidence 2) Fence-sitting 3) Hesitancy 4) Self-distrust 5) Self-doubt 6) Tentativeness 1) Hesitancy 
[n] - a feeling of diffidence about doing something
hesitant, hesitance, hesitancy, hesitantly Reluctant to do or say something because of indecision or lack of confidence.
hesitancy noun a feeling of diffidence and indecision about doing something