Synonyms for Reluctance:

n.

willing. disinclination (noun)
hesitation, doubt, hesitancy, objection, qualm, unwillingness.
dislike (noun)
indisposition.
doubt (noun)
hesitancy.
reluctance (noun)
disinclination, hesitation, hesitancy, indisposition.
unwillingness (noun)
opposition, Averseness, Repellency, balkiness, obstinacy, contrariness, unwillingness, defiance, disinclination, resistance, stubbornness, noncooperation, repugnance, distaste.

Other synonyms:

doubt. Other relevant words:
hesitation, doubt, Averseness, qualm, indisposition, hesitancy, objection.