It depends on the style guide you are following. In some cases, underlining and using quotes can both be used to indicate the title of a novel. However, in modern usage, italics are more commonly used for the titles of longer works like novels. For example, in MLA style, italics are the preferred way to present novel titles.
I usually use italics for a novel's title rather than underlining or quotes. But if you're writing by hand or in a situation where italics aren't possible, underlining can be a substitute for italics. Quotes are more often used for shorter works like short stories or individual chapters within a novel.
Well, in general, we don't really use quotes around a novel title. Underlining was more common in the past, especially in typewritten works. But nowadays, with digital writing being so prevalent, italics are the norm for novel titles. It gives a clear visual indication that it's the title of a work of significant length, like a novel, as opposed to a shorter piece which might be in quotes.
Chapter 39, "Is This Book an Out-of-Print Buddhist Scripture?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 238, "The Guests Were Dumbfounded, The Audience Was Excited", is the clearest early answer because it turns Shu Yan's situation into a concrete plot event. It opens with Jiang Li was actually first on all three leaderboards?! and closes on And, to Zhou Xu's alarm, they did find a problem..
Chapter 138, "From now on, let's get to know each other again", is the clearest early answer because it turns Shu Yan's situation into a concrete plot event. The chapter turns that into something concrete by moving from Is there such a good deal?
Chapter 91, "Jiang Yan is Number One on the Trending Searches Again?!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. It opens with When Jiang Li saw that he had been assigned a harrow, Qi Tianyu felt...
Chapter 262, "Flash Change Quartet Speaks Out for Jiang Li", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Wen Jiaojiao couldn't stand it anymore and immediately logged onto...
Chapter 208, "Those Who Commit Many Wrongs Will Destroy Themselves", is the clearest early answer because it turns Wen Jiaojiao's situation into a concrete plot event.
Chapter 201, "Passing the Door Three Times without Entering", is the clearest early answer because it pushes Jiang Li into a new phase or setting. The chapter turns that into something concrete by moving from The third time she passed by happened to be when she was rushing back...
Chapter 205, "The Fairy Descends to the Mortal World", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 38, "Pretending to be a Top Student? You Must Have Forgotten Your Own College Entrance Exam Score!", is the clearest early answer because it turns Top Student's situation into a concrete plot event.
Chapter 274, "Post-Traumatic Stress Syndrome", is the clearest early answer because it turns Hu Zi's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Upon hearing this, Officer Xu became even more excited, but catching...