Complex sentence: Bill Gates tried to recruit reluctant Allchin to join Microsoft for a year and successfully convinced him in 1990 by telling him that whatever he has created a wider customer base through Microsoft than anyone else.
Split into simpler sentences: Bill Gates tried to recruit a reluctant Allchin to join Microsoft for a year and successfully convinced him in 1990. Gates told him him that whatever he created would have a wider customer base through Microsoft than anyone else.