Confidence comes from knowing both what to do and why.
The success of the project came from the hard work of the team.
come from
- come
- 何かが起こる
- from
- 起こった起源や出所を指す
- of（原因） でもいいが、of は少し古風な言い方
自信がない
comes from knowing / まずは知ることから
come from ~｜~から起こる、生じる
Confidence comes from knowing both what to do and why.
The success of the project came from the hard work of the team.
自信がない
comes from knowing / まずは知ることから