Should the betrothed proceed with the marriage despite her dwindling feelings of love towards her fiancé, and what is the reason for this dwindling?

"The change in feelings towards the suitor is not a cause for concern, as it might be a normal occurrence caused by frequent meetings or other factors. Such meetings for acquaintance are not permissible শরীয়ত (religiously) because the fiancée is a stranger to the suitor until the legitimate marriage contract is concluded. Phone conversations between fiancés often involve lust or pleasure. The distress you are feeling might be a consequence of this religious transgression, and therefore, repentance is necessary. If the suitor is a man of good character and religious commitment, it is not advisable to leave him, as the Prophet (peace and blessings be upon him) said: 'If someone whose character and religious commitment you approve of comes to you, then marry him off. If you do not do so, there will be tribulation on earth and widespread corruption.' A change in feelings does not mean there is no good in marrying him. The benefit of Istikhara (prayer for guidance) becomes apparent in whether the marriage proceeds or not; if it proceeds, then there is good in it, and if it does not, then Allah has averted evil."