Perhaps Sarek has some sort of personal conflict within himself. Maybe he's facing some internal Vulcan political or family pressure and he thinks taking Amanda away from her normal life could be a solution. It could be related to some secret Vulcan traditions or expectations that he feels he must enforce on her.
One possible motive could be that Sarek believes Amanda is in some sort of danger and his Vulcan way of thinking makes him believe that kidnapping her is the only way to protect her. He might think that the Federation or some other force is unable to safeguard her properly.
Another motive could be related to his love for Amanda in a very twisted way. Vulcans have complex emotions even if they try to suppress them. He might think that by kidnapping her, he can keep her all to himself and away from the influences of the outside world which he might perceive as negative or corrupting.
Chapter 87 is the strongest chapter-level answer because it starts from Luckily, at that time, Jiang Li had already taken her pot of stinky... and follows through on I'm driven crazy by him every day.] [+1 from above!.
The best chapter pointer here is Chapter 66, "This Sister Really Can Hustle!". It opens with I can't take it anymore, why did the young master even find a pair of... and closes on Unable to find a staff member to notify, and not wanting to waste time for....
A practical answer is Chapter 81, because it turns the idea into a concrete scene. The chapter opens with Qi Tianyu, who chose curry beef rice, received a piece of curry and a..., adds pressure through I'm going to tell the director to deduct 10 points from you both right now!, and ends on The.
A practical answer is Chapter 77, because it turns the idea into a concrete scene. The chapter opens with Wen Jiaojiao's reminder calmed Shu Yan down., adds pressure through She would never touch anything of Jiang Li's for the rest of her life!, and ends on But who knew that the next second, the.
A practical answer is Chapter 43, because it turns the idea into a concrete scene. The chapter opens with The moment He Yun willingly sat next to Jiang Li and even took off his..., adds pressure through VIP lounges and business class still count as transformation?, and ends on Just as she turned.
The best chapter pointer here is Chapter 77, "Why are you sabotaging me again?". It opens with Wen Jiaojiao's reminder calmed Shu Yan down. and closes on But who knew that the next second, the lottery box would be handed over to....
A practical answer is Chapter 80, because it turns the idea into a concrete scene. The chapter opens with Jiang Yan and Wen Jiaojiao, one so smug he was almost ascending to the..., adds pressure through There's abalone, eels, crabs, isn't that tycoon enough?" "Hang on." Shu..., and ends on.
Look to Chapter 93 for the clearest answer. It begins with Jiang Li looked back and saw several aunties linking arms, walking up the..., keeps building through The leader was indeed the aunt to whom she had read fortunes this morning., and lands on I did the same when I was young, and when my dad.
Chapter 44 is the strongest chapter-level answer because it starts from But the next move by the production team proved they hadn't forgotten the... and follows through on Does anyone here know how to drive?.
If you want the clearest chapter reference, go to Chapter 51. Early on, Oh, okay." After uttering two syllables indifferently, Jiang Li bent down...; later, the chapter leans on By the time she reacted, Jiang Li had already disappeared at the end of....