Final answer:
In 'Sonnet 31' by Sidney, the speaker Astrophel is disappointed because Stella, the object of his love, does not return his affections, leading to a feeling of rejection. It becomes evident that Stella does not wish to engage in the romantic pursuit that Astrophel offers, leaving him feeling rejected and dejected.
Step-by-step explanation:
In Sidney's 'Sonnet 31', the speaker, Astrophel, has been disappointed by the object of his love because she does not reciprocate his feelings. Astrophel struggles with unrequited love for Stella, who appears disinterested in the game of love he is so earnestly trying to play. Despite his passionate lamentations, it becomes evident that Stella does not wish to engage in the romantic pursuit that Astrophel offers, leaving him feeling rejected and dejected.