I do not believe that self-reliance and self-trust are the same thing.
I see self-trust as being more associated with internal feelings, guidance, and perhaps even conscience. Self-reliance deals more with a person's ability to do something without the aid of anybody else.
From an early age, people develop a great deal of self-trust. They trust their own thoughts and feelings about who to be friends with, what color is their favorite, what foods they like, and when their body is tired. They trust their internal thoughts and feelings. As a person ages though, that trust may diminish as peer pressure asserts itself. That would be diminishing self-trust, but that person might be very self-reliant in a variety of areas. He or she could be fully capable of changing the oil in their car or purchasing groceries for the week. No outside help is needed. That person is self-reliant because he/she doesn't need nor want outside help; however, that person also might not have much self-trust. He/she is capable of doing the work but is not confident in which oil to use for the car or which grocery store is best for their needs. Perhaps several people gave conflicting advice, and now the person doesn't trust himself to make the best decision. I come across students like this every so often. A student is completely capable of doing the assignment, but that student has zero trust in themselves that it is done well.