I would say that it depends on how you see the role of Gertrude in the play that particularly shapes your understanding of the action and events that take place. Understanding Hamlet's perception of reality really depends on the role his mother plays in the plot and events that follow. Particularly, Hamlet's understanding of his mother's role whether it is true or just his imagination.
For example, is Gertrude to blame for her husband's murder? Was she somehow responsible for the murderous desire that inspired Claudius to kill King Hamlet? Did Gertrude invite her brother-in-law's attention, were they involved before the murder?
Or, was Gertrude used by Claudius, a manipulator and a murderer who was only interested in seizing power. She was just an extra benefit that came with the throne.
Which makes one wonder if Gertrude was really ignorant of Claudius's plot to kill her husband, and once he is dead did she not suspect him as his killer?
If you believe that Gertrude was in love with her husband, King Hamlet and did not believe that foul play was involved in his death then you have to assume that her role in the play is defined by her loyalty to the country and her desire to remain queen to maintain order and calm among the people.
If you believe that Gertrude was part of the plot to kill her husband, which is hard to imagine, although she does frustrate Hamlet with her inability to see anything sinister in her new husband's actions, then she married Claudius as a way to protect herself from being eliminated just like King Hamlet.
"Just how deeply Gertrude is involved in her second husband's plot to kill Old Hamlet is unclear; by the final scene, it seems that the Queen was ignorant of the crime. Nevertheless, she marries her brother-in-law only a few months after her husband's death."
There are many ways to interpret Gertrude, but I believe that she is sincere in her belief in the goodness of others motives, and married Claudius to keep the kingdom stable and it was common for royal wives to marry their late husband's brother. (Henry VIII married his late brother, Arthur's wife, Catherine of Aragon, she was the first wife, the true queen of England at the time.)
Interesting question. In Hamlet, you might approach women's roles as the following:
1. Ophelia as the doting, dependant lover.
2. Ophelia as the innocent maiden.
3. Gertrude as the mother figure.
4. Gertrude as a widow.
5. Gertrude may be seen as a dependant in that she marries Claudius so soon after her husband's death.
You might also want to approach the different roles along Jungian archetypes. These might include the mistress, the bit@h, the heroine, the handmaiden, the mother, star crossed lovers, the lunatic, etc. Each of these roles are merely suggestions. There's not enough room here to tackle each individually. Each of these roles or approaches might be an essay....