If I were to praise myself about one thing in my life, it would be my willingness to continue studying English even though I'm not very good at it.
この場合、次のような言い方ができますよ。
ーIf I were to praise myself about one thing in my life, it would be my willingness to continue studying English even though I'm not very good at it.
「人生において1つ自分のことを褒めるなら、いとわずに苦手な英語の勉強を続けることだろう」
one's willingness to ... で「…する意欲・いとわずに…すること」
ご参考まで!