Miscellaneous challenges, loss of control

The character having to take an emergency trip and leave their pets with someone who has never watched them
Needing a doctor to perform a lifesaving but risky medical procedure
A vacationing character enlisting a local to give them a tour around an unfamiliar city
Working on an important project with a new team
Being referred to a new professional (a financial advisor, live-in nurse, nanny, etc.) when the one the character has always used retires
A kidnapped or trafficked character being offered help by a stranger
The character becoming ill in a foreign country and having to rely on strangers for care
Engaging in an illicit activity (buying drugs, hiring a hitman, selling stolen merchandise, etc.) and trusting that the other person isn't a cop
Being imprisoned and trusting that the guards will be fair and protect the character
Relying on strangers to smuggle the character out of a hostile area or hide them from authorities

Trauma or fear clouding the character's judgment, making it difficult for them to decide what to do
An independent character having to accept help from others
Loved ones or co-conspirators disagreeing with the character's choice of who to trust
Having to relinquish control to someone else
The trusted person turning out to be incompetent, lazy, or not a good fit for the character
The person not working out, and the character having to waste more time and money finding a replacement
The character having to hold their tongue when the other person makes a decision they disagree with
Having to be comfortable with never having all the information
Asking questions the other person won't answer (because they have to keep a confidence, the truth would frighten the character, it's better if they don't know, etc.)
Having to pay for the other person's service and not knowing if the investment will pay off