“I shall marry her if I choose to” ( a case of illocutionary suicide?)

This puzzling sentence, in a slightly different formulation, appears at the top of p. 214 in “Ifs and Cans.” ( Phil Papers 3rd ed) It is followed by the equally puzzling “I intend to marry him if I choose.” I really haven’t a clue what these sentences are supposed to say or mean.

Austin has just said that “I shall” in such utterances is not an assertion of fact but an expression of intention. I agree, and that’s precisely why I don’t understand these utterances. If John says he intends to commit marriage, I make the assumption that he has already decided or chosen to commit marriage (God help him). Otherwise I don’t understand his saying he intends to marry. An intention to do X assumes a prior decision to do X. How then can I possibly declare my intention to marry someone and at the same time imply that I have not yet decided to do so? As an attempt to express an intention to marry , “I shall marry her if I choose to” seems to commit illocutionary suicide with its if clause.

“I shall marry her if/provided she consents” is fine. I express my intention to marry her, but I note, quite sensibly, that her consent is needed to make this marriage happen. Her consent is not assumed by my intention or a condition of it. Ordinary speakers understand that I’m saying “I intend to marry her, and the marriage will happen provided she consents.”