YOU SAID:

my sister is trying to learn how to play guitar

INTO JAPANESE

私の妹はギターの弾き方を学ぼうとしている

BACK INTO ENGLISH

My sister is trying to learn how to play the guitar.

INTO JAPANESE

私の妹はギターの弾き方を習おうとしている。

BACK INTO ENGLISH

My sister is trying to learn how to play the guitar.