In naruto you can determine a female ninja's skill level by the size of their breasts. Think about. Tsunades is the greatest female ninja of all time and she has the biggest largest breasts of any character in the series. Anko and Kunuri are both high level jounin ninjas and they have large chests to match up.

Temari is the bustiest of all the female genins and she is also the most skilled. Tentens comes after her in bust size and skill. Sakura and ino both suck so they are both practically flatchested to show that they have no skills what so ever. Hinita is better then either of them so of course she has a larger chest. The only potential hole in my theory is Shizune. But then again Shizune sucks which goes along perfectly with her flat as a board chest her flat chest.