Using a symbol in the title could be an issue for your book long after query stage: How will people type the title into their search engines? How will the symbol translate in databases like Goodreads and Amazon, considering databases are notorious for converting non-letters to random symbols? Even simple apostrophes in titles can get warped in email subject lines for launch announcements, etc. Is the trademark symbol vital to understanding the concept of your book and thus worth the potential hiccups in online promotion and book listings? Consider leaving it out of the official title and using it only as a design element on the final book cover. Can you skip it during submission, at least? You can discuss its necessity with your editor and marketing team later. If it must stay in the official title through all stages, add an asterisked line to the ms cover page or somewhere in the query letter’s body text, such as: *Trademark symbol is part of official book title. That may raise eyebrows for being unusual, but it’s unlikely to sabotage the manuscript.