To me, it sounds like the two are already a couple. The guy had done something in the past to hurt her. Even though he feels their relationship is stronger than it was then, she still fears he will do it again. I think he left her for whatever reason, and she asked him, "don't leave, don't give up on me" but he left for two weeks and came back. She asked him not to lie, probably about what happened during those two weeks, but he tried to explain it wasn't that way. He wants to gain her trust back, but she is still thinking about the past and what he did, and can not let it go.