Is a man's saying to a widowed woman, "You are my wife," and her acceptance of that in the presence of witnesses, considered a valid marriage (zawaj sahih) or a void marriage (nikah fasid) that necessitates divorce for her to be able to marry another, especially given her knowledge of the permissibility of marriage without a guardian (wali) according to Abu Hanifa?

Marriage is not contracted through such frivolous and objectionable speech that occurred between the man and the woman at the workplace. There is no need for divorce or annulment because it was never validly contracted in the first place. She is permitted to marry the man who proposed to her. She must repent to Allah for the objectionable speech she engaged in with that man, adhere to Allah's boundaries in dealing with non-mahram (definition) men, avoid seclusion if the work necessitates being in a mixed environment, and ensure that interactions are kept to the absolute minimum and only when necessary.