It could be about Tobi having some serious motives for tying up Sakura. Maybe he's trying to extract information from her, thinking she has knowledge that is crucial for his plans.
In the 'serious tobi ties up sakura fanfiction', it might be that Tobi believes Sakura is a threat to his grand scheme. He ties her up to keep her from interfering. It could also be a misjudgment on his part. He may think she is more powerful or involved in certain events than she actually is. This situation could lead to Sakura using her wits and medical ninjutsu skills to try and escape, or it could be the start of a complex relationship where Tobi realizes she's not what he initially thought and they have to work together in some unexpected way.
Chapter 877, "You Are Not the Real Jiang Li!", is the clearest early answer because it turns Gu Group's situation into a concrete plot event. Early on, The Gu Family values their reputation greatly and has a dedicated PR....
If you want the clearest chapter reference, go to Chapter 15. Early on, Jiang Shixu woke up from those nightmares filled with blood and darkness,...; later, the chapter leans on The two sleeping pills he took in the evening had left him with a....
Chapter 878, "Do You Dare?", is the clearest early answer because it turns Su Yinwan's situation into a concrete plot event. The chapter gives readers a real answer by opening on Su Yinwan not only chose a remote location for the meeting, but the...
A practical answer is Chapter 3, because it turns the idea into a concrete scene. The chapter opens with Qiao was still annoyed at the attitude of this unknown girl when she heard..., adds pressure through So without a second thought, she blurted out a fierce challenge, "Fine, if..., and ends on.
Chapter 898, "College Entrance Examination", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event.
Chapter 709, "But He Really Is My Second Uncle", is the clearest early answer because it turns Wen Jiaojiao's situation into a concrete plot event. It opens with The voice came from Jiang Li. and closes on However, in the original story, he did indeed lose his life there..
If you want the clearest chapter reference, go to Chapter 22. Early on, Hearing this, Su Yinwan looked at Shang Shaojing with a face full of...; later, the chapter leans on Shang, but it's not necessary; I haven't been wronged." After she spoke,....
Chapter 936, "When Did the River Moon First Shine on People [Extra: River Moon Chapter]", is the clearest early answer because it turns Shine's situation into a concrete plot event.
Chapter 691, "Sorry, You Don't Deserve It", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. It opens with As soon as Jiang Li was mentioned, Zhao Lang suddenly became...
Chapter 916, "Not Biological?!", is the clearest early answer because it turns Hong Pei's situation into a concrete plot event. The chapter turns that into something concrete by moving from Bang," Hong Pei slammed the teacup onto the table.