Answer :
I think the answer might be between "We know the project is hers' alone but are willing to help anyway." or the answer would be "We know the project is her's alone but are willing to help anyway."
Answer:
We know the project is hers alone but are willing to help anyway.
Explanation:
The correct version is the one that contains the possessive pronoun hers. Possessive pronouns mine, his, hers, its, yours, ours and theirs do not have an apostrophe and are used as nouns to avoid repetition of words. In this case, the possessive pronoun hers indicates belonging and replaces the noun phrase her project.