Final answer:
Queen Gertrude is the speaker of the quoted line from Shakespeare's play Hamlet, expressing her regret that Ophelia did not live to marry her son.
Step-by-step explanation:
The speaker of the quotation, "Sweets to the sweet! Farewell! I hoped thou shouldst have been my Hamlet's wife; I thought thy bride bed to have deck'd sweet maid, and not have strew'd thy grave," is Queen Gertrude from William Shakespeare's play Hamlet.
This line occurs in Act 5, Scene 1, during Ophelia's funeral. Gertrude is expressing her sorrow and unfulfilled wish for Ophelia to have married her son, Hamlet.
The line reflects the thematic elements of love and death that pervade the play, as well as the interplay of what might have been versus the harsh reality faced by the characters.