American-born Issac only entered the house on Wednesday, but the pair had made a pact that he would leave if she was voted out.
Noirin said: "Apparently he was meant to ask me before I kissed Siavash,"
"I love Isaac - I love him to bits. Yes, of course, I will marry him. He's just the best thing ever."
When asked if he would pop the question, Isaac joked: "That depends on how well she behaves."
The couple plan to move to America to start a new life together.