I believe his telling her to go to an abbey - as opposed to the other meaning, which is a brothel - is his way of telling her to leave before he or anyone else in the court hurts her. He also states “why woulds't thou be a breeder of
Sinners?” In this I believe he is sincerely telling her that he doesn’t want her children to grow to be sinners with an implied ‘like me.’ He wants her to stay in an abbey away from men so she can’t have children like him. I believe part of this is fueled by his disgust towards his mother who, not even two months after the elder Hamlet is killed, marries and sleeps with his brother. Hamlet’s mother is, I think, a large influence on Hamlet, being the only surviving family member that he really called family. When she married Claudius, it dealt a huge blow to her son Hamlet’s view of her, himself, and women. It changed his way of thinking to believing that all women were whores who were only in it in the sex. He began to believe women were unfaithful and would desert the man immediately after having sex with him to go have sex with another