to fail + Infinitive / not fail + Infinitive

[vil]

Dear teachers,

Would you be kind enough to explain to me the following paradox?

The combination of the verb “to fail” in its affirmative form + Infinitive of another verb has negative connotation. For example “The sellers failed to ship the goods”. = “The sellers did not ship the goods.”

The combination of the verb “to fail”in its negative form + Infinitive of another verb has a positive connotation. For example: “We will not fail to send you some copies of the catalogue.”

On the other hand there are a few further examples without usage of an Infinitive of another verbs:

The negotiations failed.
The company failed last year.

Thank you for your efforts.

Regards,

V.

[IvanV]

To fail - to be ineficient or lacking something, to perform ineffectively or inadequately.

The sellers failed to ship the goods = They were not successful in shipping the goods.
The negotiations failed = The negotiations were unsuccessful.

What do you not understand, exactly?