soothe 
(s
th)
v. soothed, sooth·ing, soothes
v.tr.1. To calm or placate (a person, for example).
2. To ease or relieve (pain, for example).
v.intr. To bring comfort, composure, or relief.
[Middle English sothen, to verify, from Old English sōthian, from sōth, true; see es- in the Appendix of Indo-European roots.]
soother n.