If you follow the details, Google tells in its blog post that this feature is a price guarantee program which is going to help in ticket booking. Many times it is seen that after booking the ticket, its price reduces, in such a case the company will offer a discount to the user. That is, after the ticket price is reduced, the remaining money will be reduced. This feature will monitor the flight price before departure daily. Also, the user will get refund with the help of Google Pay.
Also, this offer will be available on select flights only. Colorful price badges will also be given in this and these flights will depart from America only. Do remember that the Guaranteed Flight offer is applicable only when the tickets are booked using Google Flights. According to the company, any user will get a maximum of $ 500 in refund. It is also mandatory that the price difference is more than $5, only then this refund will be available.