I believe Gertrude was a woman looking out for her best interest, as all women of that time period must have had to in order to sustain her “place” in society. We don’t know what type of family Gertrude came from. Was she a descendent of royalty or from a commoner? She may have confided in Claudius prior to King’s demise. We don’t know what Claudius told Gertrude to make her fall for him or if she always loved him, but she did what she felt was what needed to be done by marrying him. Once the King was dead, she had to keep her place in proper society, so whom better to marry than her husband’s brother? She keeps her good name and last name! He likely promised her things that were lacking in her own marriage. He did state, “Things work its way out” but how was she to know what he meant exactly by that statement? Women were not to question a man in Gertrude’s day, not like in today’s world. It was a “Don’t ask, Don’t tell” type of mentality. Claudius most likely promised that she that she could keep her royal position and all would stay “status quo”. This would have please Gertrude very much and would not have worried much about Hamlet, as time heals all wounds.
She also knew that once the King was dead, if she did not marry and Hamlet returned, she would be displaced as Queen, and Hamlet would be named King and whomever he married would be the new Queen with all the royal stature that goes with it. Gertrude was not ready to give that up. No Queen wants to give up her crown while she is still in the prime of her life! She loves Hamlet, yet can be uncaring towards his feelings. An example of this is when Hamlet comes back from University to find his mother remarried to his uncle, Claudius, and he is in a foul mood and Gertrude is pestering him about it and he confronts her,