@Pocky8 : No, she said she saw nobody entered/exited the room.
She ran into him on her way out, and likely left after she pointed him to where the room is (meaning she didn't see him enter the room personally)
@HiraiiLV: Depends on your definition of 'family'.
The old royal family basically kept her out of sight and treated her like shit in the short time she's at the palace after her real mother's death.
And they were also quite the scums of a royal family as well.
Only her, the 'faceless saint' that went around using her own money to help others, were popular with the people (despite her short term as a princess and how little she could do), which is why the prince want to make her his consort (albeit he also plan to kill her if she refuse)
Do note that the prince has no idea what she looks like, the only portrait ever made of her burned down during the war.
Obviously Marie misunderstood his intention since he murdered the rest of them.