Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
We perceive that you should collect more information about this guy concerning his piety. Does he perform all of his religious obligations, especially the prayers on regular basis or not? Does he avoid committing Haram or not, etc? What his friend said about him is not enoughto evaluate him properly and assess his behaviour.
Anyway, his relations with a girl whether he loves her or not, defames his attitude and raises some doubts about his true adherence to Sharia. Furthermore, you have confirmed that he has had relations with a girl and you have seen him kissing her, this fact alone proves that he is not as pious as a Muslim should be. If you have evidence that he has made sincere repentance and that he no longer has relations with alien girls, then you may accept his proposal. Before accepting it, you should make Istikhara. How to perform Istikhara, see the Fatwas Nos. 81434 and 81992. We ask Allah to guide you to the right path and grant you a nice pious husband.
Allah knows best.