Let not thine heart
leb (labe)
the heart; also used (figuratively) very widely for the feelings, the will and even the intellect
decline
satah (saw-taw')
to deviate from duty -- decline, go aside, turn.
to her ways
derek (deh'-rek)
a road (as trodden); figuratively, a course of life or mode of action, often adverb
go not astray
ta`ah (taw-aw')
to vacillate, i.e. reel or stray; also causative of both
in her paths
nathiyb (naw-theeb')
a (beaten) track -- path(-way), travel(-ler), way.