How can I convince my mom to wear sleeveless blouses, cause she is a very conservative woman?

You have stated that you didn't t want any stupid advice, then why have you asked this question here. What is your expectation? Should Readers give answer as you like and if you don't like the advice you would describe it as foolish? I don't know what is your age but if you are major and independent, you may behave as you like. Otherwise, follow your mother. I personally don't think your mother is wrong or she is orthodox. There is no need to expose body to become reformer.