とうとう
Usage
indicates that an expected situation has occurred after an extended period of time. The adverb ついに is similar to とうとう and can be used in place of of とうとう。ついに is more formal. Finally; at (long) last; eventually; in the end; after all
Examples
とうとう博士論文が完成した。5年もかかってしまった。
Finally I have completed my doctor thesis. It has taken me 5 years.
子供の時から長い間練習し続けて、とうとうオリンピックに参加することが出来た。
Since I was a child I continued to train a lot, so in the end I could participate in the olympics.