The perlocutionary result (how the promisee reacts) might be acceptance, or skepticism, or disbelief, but none of these reactions alter the illocutionary force of the statement: the promise was made.
It is also often emphasised that Austin introduced the illocutionary act by means of a contrast with other aspects of "doing" by "speaking."
According to a widespread opinion, an adequate and useful account of "illocutionary acts" has been provided by John Searle (e.g., 1969, 1975, 1979).
Collections of articles examining Searle's account are: Burkhardt 1990 and Lepore / van Gulick 1991.
Searle (1975) set up the following classification of illocutionary speech acts: The classification is intended to be exhaustive but the classes are not mutually exclusive: John Austin's well-known example "I bet you five pounds it will rain" is both directive and commissive.
Several speech act theorists, including Austin himself, make use of the notion of an illocutionary force.
Some followers of Austin, such as David Holdcroft, view illocutionary force as the property of an utterance to be made with the intention to perform a certain illocutionary act—rather than as the successful performance of the act (which is supposed to further require the appropriateness of certain circumstances).
According to this conception, the utterance of "I bet you five pounds that it will rain" may well have an illocutionary force even if the addressee doesn't hear it.
According to this conception, the addressee must have heard and understood that the speaker intends to make a bet with them in order for the utterance to have 'illocutionary force'.
If we adopt the notion of illocutionary force as an aspect of meaning, then it appears that the (intended) 'force' of certain sentences, or utterances, is not quite obvious.