The Spaniard was influenced by a desire for game time and a manager who would suit his style, with Betis ranking high on a list of suitable clubs collated by Analytics FC, reports the Athletic.
The LaLiga outfit were in need of a regular right-back after last season's first-choice Emerson Royal returned to Barcelona after his loan ended - before he moved to Tottenham.
According to the data, playing in Spain will also increase Bellerin's chances of going to the World Cup.
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