ALACRITY

Fear :an unpleasant emotion caused by the belief that someone or something is dangerous, likely to cause pain, or a threat.
Frankness :open, honest, and direct in speech or writing, especially when dealing with unpalatable matters.
Alarm :an anxious awareness of danger, warning, alert, caveat, caution, admonition.
Briskness :active, fast, and energetic.
Alacrity :brisk and cheerful readiness.
So, Synonym of Alacrity is Briskness.