All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, is His slave and Messenger.
We ask Allah, The Exalted, to make your affairs easy, facilitate your marriage, and render it a source of happiness and comfort for you.
Your message did not include any specific question. As for the chats you had with this girl about matters that do not please Allah, The Exalted, it is incumbent on both of you to repent of it. Keep in mind that sinning may be a reason for deprivation of blessings and bounties. Allah, The Exalted Says (what means): {And whatever strikes you of disaster – it is for what your hands have earned; but He pardons much.} [Quran 42:30]
The fact that this girl changed her mind and decided to cancel the marriage plans is not necessarily due to an evil eye and the like. Nonetheless, if you believe that it is most likely because of an evil eye, then the Ruqyah (Quranic healing), which includes Quran, supplications, and Athkaar, should be recited over her, but you should beware of resorting to soothsayers and sorcerers.
There is nothing wrong, Allah willing, with reciting Soorat Al-Baqarah or other chapters of the Quran with the intention of seeking facilitation of your affairs and removal of your affliction. It was narrated on the authority of ‘Imraan ibn Husayn that he said: “I heard the Messenger of Allah say: ‘Whoever recites the Quran, let him ask Allah by it...’” [At-Tirmithi]
Al-Mubaarakfoori said in Tuhfat Al-Ahwathi: “‘let him ask Allah by it,’ means to recite the Quran and ask Allah, The Exalted, by (virtue of reciting) it for whatever he wishes of the affairs of this world and the Hereafter. It may also mean that whenever he recites a verse about the Mercy of Allah, he should ask Allah for mercy, or that he should supplicate Allah right after recitation of the Quran with the reported supplications.” [End of quote]
Thus, you come to know that this matter is not specific to reciting Soorat Al-Baqarah, although many reports were narrated about its great merit and the fact that taking it (i.e. reciting it regularly, pondering over its meaning, and acting upon its teachings) is a blessing.
Allah Knows best.