I am presently dating a Catholic girl who accept most of secularism. She supports gay marriage because she is friends with many homosexuals who are married at work. She is a wonderful and good person but seems to base every belief on what seems the nicest and not on the truth of the faith, in the end I lose respect for her inability to discern beyond the childish idea of doing what seems nice. How can I show her that there is a reason to accept Church authority at times or at least expose the fact that the difference in thinking makes us incompatible which she also doesn’t seem to notice?
Well, a couple of things.
(1) Engage her in discussion, and suggest studying the catechism and bible together, attending Mass together, watching EWTN together… and see how she responds. If her response is that she isn’t interested-- proceed no further, you have your answer.
(2) I say proceed no further because you cannot be on a mission to “improve” her for your own agenda of continuing to date her. And, frankly, if she doesn’t want improving you can’t do it anyway. If she remains satisfied in her secularism, then it’s YOU who need to make the adjustment.
(3) That adjustment would be to cease dating her and find instead a woman who shares your beliefs, vision, and values.
Perhaps begin to study the Cathecism with her?