So if bet is from make good, what word is it derrived from if any which simply means good, one cognate with French "bon" perhaps.bet 1592, probably aphetic of abet, or from beet "to make good," from O.E. bætan "make better, arouse, stimulate," from P.Gmc. *baitjanan. First surfaced in argot of petty criminals. The original notion is perhaps to "improve" a contest by wagering on it. Used since 1852 in various Amer.Eng. slang assertions (cf. you bet "be assured," 1857).
Not clear about brood and breed:
brood O.E. brod, from P.Gmc. *brod (cf. M.Du. broet, O.H.G. bruot), lit. "that which is hatched by heat," from *bro- "to warm, heat," from PIE *bhre- "burn, heat, incubate," from base *bhreue- "to boil, bubble, effervesce, burn" (see brew). The verbal figurative meaning ("to incubate in the mind") is first recorded 1571, from notion of "nursing" one's anger, resentment, etc.
breed O.E. bredan "bring young to birth, carry," also "cherish, keep warm," from W.Gmc. *brodjan (cf. O.H.G. bruoten, Ger. brüten "to brood, hatch"), from *brod- "fetus, hatchling," from PIE *bhre- "burn, heat" (see brood). Original notion of the word was incubation, warming to hatch. Breeding "good manners" is from 1596.