Se porter comme un charme is a fun little French idiom that translates literally to “to feel like a charm”. Porter means to carry or wear but here as a pronominal verb se porter means to feel. The real translation is “to feel as fit as a fiddle”.
J’ai arrêté de fumer, je mange bien et je fais du sport régulièrement. Je me porte comme un charme. I stopped smoking, I eat well and I exercise regularly. I feel fit as a fiddle.