While breaking down in tears she continued doing her best and was finally able to make it.
She really wanted to make it for everyone. She failed and failed but while breaking down in tears she continued doing her best and was finally able to make it.
ご質問ありがとうございます。
「泣きながら頑張ってそれを作れるようになった」は英語で「While breaking down in tears she continued doing her best and was finally able to make it.」と言えます。
また、「彼女はどうしてもみんなにそれをあげたかった。何度も何度も失敗をして、泣きながら頑張ってそれを作れるようになった。」も英訳すれば、「She really wanted to make it for everyone. She failed and failed but while breaking down in tears she continued doing her best and was finally able to make it.」になります。
ご参考になれば幸いです。