How does the psychological state expressed in a speech act differ from its propositional content?

In the philosophy of language developed by John Searle, the psychological state expressed by a speech act is distinct from its propositional content.

The expressed psychological state refers to the specific mental condition—such as a belief, desire, or intention—that a speaker necessarily conveys by performing a particular type of speech act. For example, when a speaker says, "It is raining," they are expressing their belief that it is raining. When they issue an order like "Get me some raisins," they express a desire that the hearer perform that action.1

In contrast, the propositional content is the specific state of affairs or action being described or referenced, independent of the speaker's mental attitude toward it. In the examples above, the propositional contents are simply "that it is raining" and "that the hearer gets the speaker some raisins," respectively. While the psychological state captures the speaker's internal orientation (e.g., believing or desiring), the propositional content identifies the subject matter of the utterance itself.1