allayer

from WordNet (r) 3.0 (2006)

allayer
    n 1: a person who reduces the intensity (e.g., of fears) and
         calms and pacifies; "a reliever of anxiety"; "an allayer of
         fears" [syn: {reliever}, {allayer}, {comforter}]

from The Collaborative International Dictionary of English v.0.48

Allayer \Al*lay"er\, n.
   One who, or that which, allays.
   [1913 Webster]