All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Firstly, we would like to underline that exaggeration in seeking an ideal suitor, especially in secondary attributes such as wealth and the like, may make the woman miss out on good marriage opportunities until she eventually finds herself obliged to accept the proposal of any suitor, no matter what he is like.
As for your question, the Prophet, sallallaahu ‘alayhi wa sallam, guided to the correct criteria for choosing a spouse. He, sallallaahu ‘alayhi wa sallam, said, "If there comes to you a suitor with whose character and religious commitment you are pleased, then marry off (your daughter or female relative under your care) to him, or else there will be turmoil (Fitnah) in the land and widespread corruption." [Ibn Maajah and At-Tirmithi]
However, this does not mean neglecting other factors when choosing the future spouse. Rather, it means that religious commitment and good manners should be given priority over other attributes. If a pious and well-mannered suitor proposed to a woman for marriage but his financial situation is not as desired, then the basic principle is that he should be accepted because the basis of a happy marriage is the fulfillment of the rights of one another and overlooking the faults and mistakes as well as refraining from harming one another. One hopes to find such behavior from a pious and well-mannered man.
However, the woman and her Wali (guardian) have the right to reject such a suitor and seek a rich, pious, and well-mannered one. A woman consulted the Prophet, sallallaahu ‘alayhi wa sallam, regarding the marriage proposal of Mu‘aawiyah ibn Abi Sufyaan to her. Thereupon the Prophet, sallallaahu ‘alayhi wa sallam, said, "As for Mu‘aawiyah, he is a pauper without money." [Muslim 2/1114] He, sallallaahu ‘alayhi wa sallam, advised her to refuse the marriage proposal of Mu‘aawiyah because he had no money.
Ibn ‘Abd Al-Barr wrote, "His words, 'a pauper without money', indicate that money is one of the requirements of marriage and desired traits in a suitor and that poverty is one of his defects." [Al-Istithkaar 6/171]
Hence, there is no harm in refusing your daughter's suitor for the reason mentioned in the question, even if he is religiously committed and well mannered. For more benefit, please refer to fatwa 90797.
Allaah knows best.