From, The 48 Laws of Power by Robert Greene and Joost Elffers:
Enter Action with Boldness
If you are unsure of a course of action, do not attempt it. Your doubts and hesitations will infect your execution. Timidity is dangerous: Better to enter with boldness. Any mistakes you commit through audacity are easily corrected with more audacity. Everyone admires the bold; no one honors the timid.
The other 47 laws are worth reading.