I came across this sentence in The Free Online Dictionary: ‘‘I don’t know but what I’ll go.’’ Does it mean something like: All I know is that I’ll go – ‘go’ as in ‘die’? (I’ve been thinking long and hard as to what it might mean, so I really have to know! :))
I believe it means “I think I’ll go” or “I intend to go”. “I don’t know but what…” = “I don’t know but that…” is an old-fashioned or dialect form of words. The use of “what” instead of “that” sounds somewhat illiterate to me, but either way the expression is not used in standard modern English.