What does Gertrude say that she had hoped about Hamlet and Ophelia?
If one recalls the scene in Act IV in which a mad Ophelia returns after the arrival of Laertes and distributes various herbs and wildflowers that have symbolic meanings, there seems an irony to the "pernicious woman's" (as Hamlet called her),the queen's statement of "Sweets to the sweet" as she distributes flowers upon the grave of the tragic Ophelia. For, critics see Ophelia as representative of the ideals of youth and innocence that are corrupted by the Danish court in "Hamlet." Perhaps, the perceptive and jaded queen's regret that Ophelia and Hamlet have not married is in her act of casting the "sweet" flowers that will die atop the "sweet" girl: All hope of decency with the marriage and life of the youths is buried.
At Ophelia's funeral, Gertrude says that she had hoped Ophelia would be Hamlet's wife. This is just after she has thrown flowers or petals on her grave and given the famous line, "Sweets for the sweet." It is at this point that Hamlet fully realizes it is Ophelia who is being buried and he is horrified. He eventually jumps into her grave and has a shouting match with Laertes over who loved Ophelia more.