ESP32 Self-sign certificate acceptance

[minhlee@1234]

Hi everyone,
Currently I'm trying to make ESP32 to accept my self-sign cert without setting insecure connection. My environment is PlatformIO with ESP-IDF framework, so I have access to the library mbedtls. I use the function mbedtls_x509_crt_verify, and currently I see that it relies on the list of trust ca to verify. I want to add my own ca in the trusted list. How can I do that?