These is too many variables not knowing your location. The plant being on a window sill indicates the pot is not big enough, get it in a 5 gal pot. Better, transplant to outside and get it one or two buddies. This plant gets about 5 ft tall as an average; and as tall as 8 ft. I believe the plant is self pollinating, but cross pollen from other like plants still helps. ... Once the plant gets happy, it will set fruit.
For growing info, See
How to Grow the Carolina Reaper plant and pepper