In general, quotations are used for titles of novels. Underlining is not a common way to indicate a novel. This is a standard convention in writing and publishing.
Writing quotations in a story involves capturing the essence of the character's speech. Make it vivid and engaging. Ensure the quotations add depth and authenticity to the narrative. Sometimes, a well-placed quotation can be a turning point or reveal hidden emotions.
Typically, novels are italicized. This is a common convention to distinguish them from regular text. Underlining is less common for novels, and quotations are more often used for shorter works like short stories or articles.
I'm not aware of any specifically titled 'Churchill romance novels'. Winston Churchill was mainly known for his political works and leadership, not typically associated with the romance novel genre.