The phrase "be obliged to" is often used to express a sense of duty or responsibility towards something or someone. It is a formal and polite way of acknowledging an obligation. There are several synonyms that can be used in place of this phrase, including "have to", "must", "need to", "required to", "ought to", and "should". All of these phrases have a similar meaning to "be obliged to" and can be used depending on the context and level of formality required. It is important to choose the appropriate synonym to accurately convey the intended message.