You are given a sentence in Japanese. Your job is to translate the Japanese sentence into Spanish.

上手く彼女になりきれていなかったことを申し訳なく思いました

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Y me sentía mal por no haber hecho un buen trabajo.