soft·en 
(sôfən, sŏfən)
(sôfən, sŏfən)v. soft·ened, soft·en·ing, soft·ens
v.tr.
1. To make soft or softer.
2. To undermine or reduce the strength, morale, or resistance of.
3. To make less harsh, strident, or critical: softened the last paragraph of the letter.
v.intr.
To become soft or softer.
soften·er n.