There is no true reality per sayse as Morpheus mention on the movie reality is nothing but electrical signals interpreted by the mind. The Thomas living in the matrix was as real as Thomas living outside the matrix. The differences is that he conformed to the reality of the matrix since he was in ignorance. Reality is more of a contextual reality. Neo asked trinity that he had memories of the time he was inside the matrix, and what did that meant, if it was not real? She responded that the matrix cant tell him who he really was.
Reality IS in fact what you want it it to be. Just like the little boy at the Oracle's apartment bending the spoon tells Thomas that he can't really bend the spoon. Bending the spoon is impossible. that which bends is only one's self. since there is no actual spoon. spoon is only a concept created by the mind to aid in the mutual understanding of a tool that is used in the aid of eating. but if there are no minds to conceptualize the idea of a spoon then spoon does not truly exist.
The oracle never lied to Thomas, since she only reaffirmed to Thomas's self answer of him not being the "one". Since he did not believe he was the one he was not the one at that point but only until he started believing in himself did he turned into the one. she did hinted though that he had the gift. The oracle would not truly had known since it depended on Thomas's choice the actual outcome of him being the one or not. Hence he started beliving he was was and changed his reality.
