After Seraphina kissed Linsley, he prepared their breakfast and ate with her in the dining room.
While they were having breakfast, Linsley recounted his experiences to Seraphina. He told her about his identity as an Avatar Master and even revealed that his abilities were from another world.
However, he never mentioned anything about the God Simulator System. He only alluded to making a pact with an unknown god from another multiverse.
Anyway, Linsley had read a lot of novels in his past life, so he easily made up a lot of things that seemed to be true. At least, Seraphina didn't find it unusual or, more like, she really didn't care where Linsley got his powers since she knew that he was a nice person.
What mattered was that they were both on the same side and were planning to overthrow the Outer God and free humanity from the Outer God's enslavement.