buy into

/B AY1 IH0 N T UW1/
verb
  1. 1

    To believe; to accept a craze or fad as valid.

    โ€œI don't buy into all this propaganda.โ€

  2. 2

    To buy stocks or shares of (a business).

    โ€œWe bought into a local electrical firm.โ€

Synonyms

Source: https://en.wiktionary.org/wiki/buy%20into