Which term describes a relationship where one party trusts another to act in their best interest?

The term that describes a relationship where one party trusts another to act in their best interest is a fiduciary relationship. In this type of relationship, the fiduciary is obligated to put the interests of the other party before their own, demonstrating a high level of trust, confidence, and legal duty. This is often seen in contexts such as financial advisors managing a client's investments, where the advisor must prioritize the client's financial well-being over their own compensation or benefits.

In contrast, a transactional relationship typically implies a more superficial interaction focused on specific transactions without the inherent trust or duty to prioritize another's interests. A professional relationship may involve trust, but it does not necessarily impose the same legal and ethical obligations as a fiduciary relationship. Similarly, a contractual relationship is typically bound by specific agreements and obligations within a defined scope, without the inherent duty of care expected in a fiduciary context.