What is the ruling if the two witnesses did not hear the woman giving her consent to the marriage?

In order for the marriage to be valid, it is stipulated that
the marriage contract should be done by the woman’s guardian, and that it
should be witnessed by two Muslim male witnesses, because the Prophet
(blessings and peace of Allah be upon him) said: “There is no marriage
except with a guardian.” Narrated by Abu Dawood (2085), at-Tirmidhi (1101)
and Ibn Maajah (1881), from the hadith of Abu Moosa al-Ash‘ari; classed as
saheeh by al-Albaani in Saheeh at-Tirmidhi.

And he (blessings and peace of Allah be upon him) said:
“There is no marriage except with a guardian and two witnesses of good
character.” Narrated by al-Bayhaqi from the hadith of ‘Imraan and ‘Aa’ishah;
classed as saheeh by al-Albaani in Saheeh al-Jaami‘, no. 7557.

The woman’s guardian is her father, then her father’s father,
then her son (if she has one), then her full brother, then her brother
through her father, then  the son of her full brother, then the son of her
brother through her father, then her paternal uncle, then his son, then the
Muslim ruler.

Al-Mughni
(9/355)

If the woman is a Muslim, it is stipulated that her guardians
should also be Muslim.

Ibn Qudaamah (may Allah have mercy on him) said:

With regard to a disbeliever, he has no guardianship over a
Muslim woman under any circumstances, according to the consensus of the
scholars, including Maalik, ash-Shaafa‘i, Abu ‘Ubayd and as-haab ar-ra’y.
Ibn al-Mundhir said: Those scholars from whom we acquired knowledge
unanimously agreed on this point.

End quote from al-Mughni (9/377)

Based on that, if your guardian is a Muslim, then the
condition of having a guardian was fulfilled.

But if he was not Muslim, then the marriage contract is not
valid, and must be repeated at the hands of your Muslim guardian, if you
have one. If you do not have one, then the Muslim judge must do your
marriage contract, if there is a Muslim judge; otherwise it may be done by
the director of the Islamic centre or someone of similar standing among the
Muslims. If no such person is available, then a Muslim man of good character
may do your marriage contract.

With regard to witnesses, what is meant is that the marriage
contract must be witnessed by two Muslim witnesses who are present at the
marriage contract that is done between the guardian and the suitor. Everyone
who is present at the marriage contract, such as a scribe, relative,
official and so on is a witness to it, if he is fit to be a witness, i.e.,
he is a Muslim of good character.

Many of the scholars are of the view that if the marriage is
publicised widely and announced, there is no need for there to be witnesses,
because of the report narrated by Ahmad from ‘Abdullah ibn az-Zubayr (may
Allah be pleased with him), according to which the Prophet (blessings and
peace of Allah be upon him) said: “Publicise the marriage.” This hadith was
classed as hasan by al-Albaani in Irwa’ al-Ghaleel no. 1993.

Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him)
said: Undoubtedly marriage that is publicised widely is valid, even if it is
not witnessed by two witnesses. But if it is done in secret and with
witnesses, this is something that is subject to further discussion.

If it is both witnessed and widely publicised, then there is
no dispute that it is valid.

If there are no witnesses and it is not widely publicised,
then it is invalid according to the majority of scholars, and if there is
any differing opinion it is insignificant.

End quote from al-Ikhtiyaaraat al-Fiqhiyyah, p. 177

See also the answers to questions no.
124678 and 112112

Based on that, if these two witnesses witnessed the marriage
contract, or the marriage was widely publicised and announced, then your
marriage is valid; if that was not the case, then you must do a new marriage
contract.

And Allah knows best.