The closest and most common synonymous phrase is supported by reality.
From comments under the question, the desire to come up with a synonym for confirm is based on not wanting to repeat confirm after having used it in a previous sentence.
When you say that something is confirmed by reality, you are saying that you have a statement about something and that reality is demonstrating it to be true. in short, reality strengthens your claim.
When using confirm here, it is in the following sense:
2 : to make firm or firmer : STRENGTHEN
// confirm one's resolve
As such, I would say that the word with the closest synonymous sense is support:
2 c: to provide with substantiation : CORROBORATE
// support an alibi
I checked this by looking at Google Ngram Viewer. I entered several search terms, and it ranked them in descending order of commonality when used in print:
- supported by reality
- confirmed by reality
- sustained by reality
- corroborated by reality
- verified by reality
- substantiated by reality
- strengthened by reality
- endorsed by reality
In fact, supported by reality is more common than confirmed by reality.