not a fool

[color=red]1-I was not a fool to accept their offer.
[color=indigo]2-I was not stupid to accept their offer.

Can’t these sentences mean two things:

a-I did accept their offer and that was not a foolish thing to do.
b-I did not accept their offer. That would have been a stupid thing to do.

Gratefully,
Navi.

No, the only possible meaning is (a).

For meaning (b), we would say, “I was not fool enough to accept their offer,” “I was not enough of a fool to accept their offer,” or, “I was not stupid enough to accept their offer.”

Thank you very much Jamie,

How about these:
[color=red]
3-I am not a fool to believe he is my friend.
[color=indigo]4-I am not stupid to believe he is my friend.

Do they mean:
a-I believe that he is my friend and that is not a foolish thing to do.
or:
b-I am not foolish enough to believe he is my friend.

I would assume that they mean ‘a’, but I am not sure. Maybe the fact that the tense has been changed changes the meaning.

Gratefully,
Navi.

The meaning is (a) in both cases.

Interesting. By the looks of it, ‘I was not stupid/a fool’ alone would stand for ‘I did accept it’, while ‘I was not stupid/ fool enough’ would mean otherwise. If so, ‘I was not so stupid as to take…’ should equal ‘It was wise to not take…’ and ‘I was not so stupid as not to take…’–‘It was wise to take…’
• Also, I wonder if there’s any need in Perfect construction ‘I was not stupid/a fool to’ve taken’ (the action did happen in the past).