Can I ask for a narrower rent guarantee without letting my daughter down?

My daughter sent the form with a message: "Just your signature and we can stop looking." Her share of the proposed rent is £700. The tenancy lists three students and a total monthly rent of £2,100.

This is in England. I said I could consider guaranteeing her rent, then read wording about all liabilities under the tenancy. I can't tell whether it limits the guarantee to her share, covers damage, or continues if the arrangement changes. The agent wants it back within two days. My daughter says asking questions now will make her friends think she isn't reliable.

[Citizens Advice's guarantor guidance](https://www.citizensadvice.org.uk/housing/starting-to-rent-from-a-private-landlord/using-a-guarantor/) warns that a guarantee for a joint tenancy can cover all the rent, and that the exact agreement matters. That is a much bigger commitment than the conversation we had at the kitchen table.

I could cover a missed £700 payment if needed. I couldn't comfortably support the whole household for several months. How do I ask the agent to clarify or narrow the guarantee while being honest with my daughter about the help I can offer? I haven't signed, and I don't want the deadline to make my answer for me.