Sounds like you don’t have any red flags. Read through some of the appeal threads to read some stories, but most refuses are because the visa officer believes the marriage is not genuine. Things that make them think this include, lack of evidence of relationship, parents and friends unaware of relationship, large age gaps, multiple divorces or past failed sponsorships, major cultural differences, very short courtships, one person doing all the financial support, and they look more closely at particular countries they believe to be high risk for marriage fraud. If they suspect these things you would be called for an interview. Your insurance should not be a problem. Another reason for refusal is misrepresentation if you lie in your application.
Short courtship is often like a Canadian visits a country and spends a few weeks there, meets someone and leaves, and returns and marries them a few months later, or if a couple has met online maybe they’ve only met in person twice before getting married etc. Or gets married after 3 months of knowing someone. But even then, these can still be approved as no one says you can’t do this, it’s just going to make a VO look more carefully.
