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.
There are two points:
First: you should sever this relationship and stop engaging in conversations with this girl, going out together, being in seclusion with each other, and the like. Your previous actions are forbidden because the wish to marry a woman or being engaged to her without having a marriage contract approved by the Sharee‘ah (Islamic law) does not permit you to look at her except within the limits of looking at things which urge you to marry her, in the presence of one of her Mahrams (non-marriageable male relatives). Then, the suitor should stop doing so until he concludes the marriage contract.
Second: after you both repent from the sins you have committed, you have the choice either to marry this girl even if she has bad breath, or leave her and marry another.
Allaah Knows best.