i have a very timid,scared female bullmastiff

hi i received a female bullmastiff from a registered breeder as he no longer wanted/needed her ,from day 1 she was scared to walk on grass,petrified of people and noises.ive had her around 1.5 years now and she is nows 5 ,she is desexed,she has slowly come around to myself mainly and has just started running up to me tail wagging and plays,but is still somewhat scared of strangers and noises,i spend hours with her daily ,introduce her to my grandkids and family but still very timid towards others ,what can any one recommend to help her overcome these sad behaviours