3 sentences

1. 经过不懈的努力，他终于成功了。

   jīng​guò bù​xiè de nǔ​lì, tā zhōng​yú chéng​gōng le.

   Through unremitting efforts, he finally succeeded.

   Source: Dong Chinese Dictionary

2. 经过不懈的努力，他终于取得了成功。

   jīng​guò bù​xiè de nǔ​lì, tā zhōng​yú qǔ​dé le chéng​gōng.

   Through tireless efforts, he finally achieved success.

   Source: Dong Chinese Dictionary

3. 他一生都钟情于航天事业，并为此不懈努力。

   tā yī​shēng dōu zhōng​qíng yú háng​tiān shì​yè, bìng wèi cǐ bù​xiè nǔ​lì.

   He was devoted to the cause of aerospace throughout his life and worked tirelessly toward it.

   Source: Dong Chinese Dictionary