Insects should take of pollination; they should be self-pollinating. Maybe a couple of months until fruit are ripe.
Have you eaten one? The flavor is very intense, reminds me of some halloween candy. The aroma is the same peanut butter scent as when you pull up a wild bitter melon vine.
I have a tree that was about 3' when I put it in the ground 2 yrs ago. It is now about 12-15'. Although there isn't a whole lot of pulp on each fruit, the number of fruit increases considerably as the matures. It is great as an off the tree snack. When you get lots of fruit it is great as a shake; blend with vanilla ice cream in a blender for a special treat.
Also, if you eat them before they soften (they get very soft when ripe) they taste somewhat like a carrot..