My 4 year old refuses to go to play school and cries every day when I leave him in playschool. Any tips to improve this??

My friend had to keep explaining to her daughter that playschool is just a few hours a day and that mummy will be back to fetch her in the evening. She kept stressing that to her daughter that it is because mummy and daddy had to work, so they had to put her in the play school. She also tells her that she can make friends and play fun stuff there. Still, tears are expected and my friend said one could only persevere through it so that the child could adapt. She suggests giving your child his comfort item (favourite toy) to bring along may help. She also said that she tries to keep her goodbyes short (as short as possible) and leaves after handling her child over to the teachers.