"… how can you trust him not to stuff up a high speed rejected takeoff. Answer: You cannot,"
Yet the industry requires that this other pilot be able to detect your mistake, intervene, and take control; the paradox of CRM.
How can you trust yourself, your judgement of others, your judgement in unexpected situations.
"Even the best pilots can make the worst mistakes" - James Reason
https://aerossurance.com/safety-mana...or-management/
For a more productive line of thought, start with the technicalities of the situation.What detection and reaction times are assumed in regulation; what are the critical piloting actions.
What situational aspects could reduce the margins of safety - very wet runway, crosswind; what is the likelihood of encountering these, how do you judge their effect before the event.