Something that ever slightly irritates me: skeptical word aversions! I'm not allowed to "know" anything because that would imply that I'm dogmatic. I'm not allowed to "believe" anything, because science isn't about belief. I'm not allowed to "prove" anything because science can never prove anything. Seriously, relax!
I think all of us here realize that scientific proof is not absolute. I think we all realize that very little is truly certain. Does that mean that we have to constrain our language?
I find I have a habit of inserting lots of qualifiers into my language, such as "I think", "it seems that", or "nearly". I try to cut down on the qualifiers, because I want to have more language variety. It should go without saying that everything I ever write is only something that I think. Explicitly saying "I think" serves only to emphasize. It's there to emphasize uncertainty, or show unwillingness to speak for other people, or simply for style. I might have similar reasons for wanting to use a word like "know" or "believe". I don't see why these word-options should be off-limits.
There is a certain breed of essay that draws fine distinctions between words. Many draw a distinction between belief and acceptance. See, belief means dogmatically accepting things despite evidence to the contrary. Acceptance means tentatively believing things because they're currently backed up by evidence. The fundamental flaw with this type of analysis is that I have no reason to agree with the definitions. Maybe when some people say they believe, they mean taking as an article of faith, but that's not what I mean. When I say I believe in science, I mean that I believe in all the established scientific theories because they have been established by sound practice of the scientific method.
Colloquially, the difference between synonyms like "accept" and "believe" is just a matter of connotation and context. "Belief" is indeed used a lot in the context of religion. That doesn't mean religion is its only appropriate context. It does, however, mean that it carries a tiny bit of religious connotation wherever it goes. So I understand wanting to avoid the word most of the time. I understand wanting to draw a distinction between religious and scientific knowledge at every mention. But there's no reason to be anal about word distinctions when they don't even concretely exist. If you can explain the difference between "acceptance" and "belief", then you can also explain the difference between "scientific belief" and "religious belief".