'Sooth' definitions:

Definition of 'sooth'

noun

Truth or reality; "in sooth"

From: GCIDE

Sooth \Sooth\, n. [AS. s[=o][eth]. See Sooth, a.]
1. Truth; reality. [Archaic] [1913 Webster]
The sooth it this, the cut fell to the knight. --Chaucer. [1913 Webster]
In sooth, I know not why I am so sad. --Shak. [1913 Webster]
In good sooth, Its mystery is love, its meaninng youth. --Longfellow. [1913 Webster]
2. Augury; prognostication. [Obs.] [1913 Webster]
The soothe of birds by beating of their wings. --Spenser. [1913 Webster]
3. Blandishment; cajolery. [Obs.] --Shak. [1913 Webster]

From: GCIDE

Sooth \Sooth\ (s[=oo]th), a.; also adv. [Compar. Soother (s[=oo]th"[~e]r); superl. Soothest.] [OE. soth, AS. s[=o][eth], for san[eth]; akin to OS. s[=o][eth], OHG. sand, Icel. sannr, Sw. sann, Dan. sand, Skr. sat, sant, real, genuine, present, being; properly p. pr. from a root meaning, to be, Skr. as, L. esse; also akin to Goth. sunjis true, Gr. 'eteo`s, Skr. satya. [root]9. Cf. Absent, Am, Essence, Is, Soothe, Sutee.]
1. True; faithful; trustworthy. [Obs. or Scot.] [1913 Webster]
The sentence [meaning] of it sooth is, out of doubt. --Chaucer. [1913 Webster]
That shall I sooth (said he) to you declare. --Spensser. [1913 Webster]
2. Pleasing; delightful; sweet. [R.] [1913 Webster]
The soothest shepherd that ever piped on plains. --Milton. [1913 Webster]
With jellies soother than the creamy curd. --Keats. [1913 Webster]