Is a legitimate marriage valid if each party says to the other, "I marry myself to you," in the absence of the guardian and the wife's brothers due to their distance and preoccupation?

For the validity of a marriage contract (nikah), the presence of a guardian (wali) for the woman is a condition, based on the Prophet's (peace be upon him) saying: "There is no marriage except with a guardian." The guardian can delegate another Muslim to complete the contract. It is obligatory to avoid forbidden relationships, private seclusion with the woman, and looking at her before a lawful, شرعي marriage.