Explain moves on "Show Moves"

I use the chess.com coach - and sometimes it'll mark a move I've made as a mistake.
Often it's obvious why as there's an obvious consequence on one move;

Sometimes the consequence is less obvious but the sequence of moves is all very clear (like creating checks that need to be responded to or very clear threats to key pieces).

But from time to time I get a "Mistake" where the 'moves' that my opponent will supposedly make bewilder me and are not what I would play at all (even after careful analysis) - granted I'm not very good at chess, so I'm left wondering why my move was a mistake at all!

Is there a way of having Stockfish / the coach explain the moves that follow a "Best move" sequence?

For example on this game: https://www.chess.com/game/live/68512510775
the 11th move `b3` is a mistake - but the suggest move knight d5 - I don't understand why the opponent wouldn't just threaten my knight with the c3 pawn afterwards rather than defend the pawn and give away a bishop - (for example - threating the knight would still allow me to play knight to c3 and threaten a fork, pushing the queen to defend the knight which would allow me to take the bishop with my queen. It's not obvious to me that the queen ending up in a slightly worse position is worth losing a piece and gaining nothing in return though.

There's are some move explanations. But engines just give lines and code has to be written to attempt to make that understandable, and in many cases that is very hard. It's hard for humans sometimes too. 

Nd5 threatens Nxc7+ and capturing the bishop