Naruto love Sakura, everyone knows that. But sadly Sakura inlove with Sasuke and Sasuke was in love with Sakura too. Naruto keep positive thinking about it, but it's clearly hurt.

The most hurting moment is when Naruto trapped by Sakura to drink gender changed potion and that day Naruto doing "that" with Sasuke. Because it's all Sakura and Sasuke plans to get child.

Eventually after that day Naruto indeed pregnant with Sasuke child, yet Sasuke didn't care about it, day and night Naruto tormented by her pregnancy, and when she was childbirth she almost lost her life yet no one cares, Sasuke and Sakura take the black haired baby and leave Naruto with the yellow haired baby one.

In the end of her life, she see you look pity with her condition, you heal her, safe her with your chakras and gave Naruto shelter to be alive with her child.