"Bought into" is a phrase that means accepting an idea, concept or belief without question or skepticism. There are several synonyms that can be used interchangeably with this phrase, such as embraced, adopted, accepted, subscribed, and endorsed. All these words describe the action of agreeing with or supporting a notion without any reservation. The synonyms imply that the person has given their full support to the concept, and they have invested their faith, time, and efforts in it. The use of these alternative words can provide more variety and emphasis to the statement while conveying the same meaning.