We can rely on identity assertions made by this certificate.
We can rely on identity assertions made by this certificate as long as they are corroborated by other marginally-trusted certificates.
We should never rely on identity assertions made by the certificate.
This certificate is an undeniable root of trust (e.g. normally, this is a certificate controlled by the user themselves).
We do not have enough information to decide whether to rely on identity assertions made by the certificate.
We do not know whether to rely on identity assertions made by the certificate.
The trust level of a certificate. Trust level tries to answer the question: "How much is the user willing to rely on cryptographic identity assertions made by the owner of this certificate?"
By way of comparison with web browser X.509 certificate validation stacks, the certificate of a "Root CA" has
GMIME_TRUST_ULTIMATE,
while the certificate of an intermediate CA hasGMIME_TRUST_FULL,
and an end-entity certificate (e.g., with CA:FALSE set) would haveGMIME_TRUST_NEVER
.