To me there seems like a very easy fix for this.
Something like this....
“I don’t believe in same sex marriages. Under current law, I am legally required to make you a cake if you ask me to. I must warn you though that I consider making cakes an art. I do it because I enjoy it. I am good at it because I enjoy it. If I am compelled by the force of government to make your cake, I will not enjoy it. This will probably result in me not doing a very good job. If you are o.k. with a cake that isn’t made right and doesn’t taste good, then we can move forward with this government mandated transaction.”
You mean well, but you apparently have no idea how activists work. They seek out Christians who offer wedding services and do whatever they can to entrap them, then sue. No amount of explaining or good will can deter their objective to create a lawsuit and reap the rewards. The 70-something-year-old
florist whose customer sued her was a long-time customer whom she treated with great courtesy and even affection, but explained that her convictions wouldn't allow her to do a good job. His "fiancé" posted the conversation on social media, drawing the attention of local gay activist lawyers as well as hate mail to the florist, and the next thing you know, this elderly lady was in danger of losing her home as well as her business. Just one story among many across the country. The courts ruled against her religious rights and now she is a continuing target of activists.