Did Sarah lie to Chuck in 1.08 Truth, when he asked her if their thing under the undercover thing was going anywhere, and she said, “Sorry, no.” We are supposed to think Sarah’s answer wasn’t the truth because of all the effort she put in resisting the effect of the truth serum but, from the way Chuck phrased the question, technically she didn’t lie—she really didn’t see a future for them. She didn’t for the first two seasons.
And neither did Chuck. In 1.08 Truth, Chuck broke up with Sarah because she said they had no future together. In 2.03 Break-Up, Chuck broke up with Sarah because he said they had no future together.
1.08 Truth was the real break-up of their fake relationship because Chuck thought Sarah’s feelings for him were not real and he wanted something real, so he broke up with her for his sake, while 2.03 Break-Up was the fake break-up of their real relationship because Chuck thought Sarah’s feelings for him were all too real and a danger to her life, so he broke up with her for her sake.
But both thought that she was going to leave once the Intersect mission was over because she was a super spy and he was just a normal guy.