Yes, God will forgive you. “Full knowledge” comes up in determining which sins are mortal and which are venial - a mortal sin results in the loss of salvation, venial sins do not. Any sin can be forgiven if you repent. . .
Laudetur Iesus Christus.
This issue of being forgiven and the state of grace is a difficult one:
But as to what thy Sweetness has added in thy letters, namely that thou wilt continue to be urgent with me till I write that it has been revealed to me that thy sins are forgiven, thou hast demanded a difficult, nay even an unprofitable thing; difficult indeed, because I am unworthy of having a revelation made to me; but unprofitable, because thou oughtest not to become secure about thy sins, except when in the last day of thy life thou shall be able no longer to bewail them. But, until that day comes, thou oughtest, ever suspicious and ever fearful, to be afraid of faults, and wash them with daily tears. Assuredly the apostle Paul had already ascended into the third heaven, had also been caught up into Paradise, and heard secret words which it was not lawful for a man to speak (2Co 12,2, &c)., and yet, still fearful, he said, I keep under my body, and bring it into subjection, lest that by any means, while preaching to others, I myself should become a castaway (1Co 9,27). One who is caught up into heaven still fears; and shall one whose conversation is still on earth desire already not to fear? Consider, most sweet daughter, that security is wont to be the mother of carelessness. Thou oughtest not, then, in this life to have security, whereby thou mayest be rendered careless. For it is written, Happy is the man that is always afraid (Pr 28,14). And again it is written, Serve the Lord in fear, and rejoice unto him with trembling (Ps 2,11). In short, then, it must needs be that in the time of this life trembling possess your soul, to the end that it may hereafter rejoice without end through the joy of security. May Almighty God fill your soul with the grace of His Holy Spirit, and, after the tears which you daily shed in prayer, bring you to eternal joys. (St. Pope Gregory the Great, Epistle XXV, to Gregoria, 20725.)
A pleasing illustration of this attitude is found in the reply of St. Joan of Arc to a question posed as a trap by her ecclesiastical judges: “Asked if she knew that she was in God’s grace, she replied: ‘If I am not, may it please God to put me in it; if I am, may it please God to keep me there.’” (1997 Catechism of the Catholic Church 2005)
One of the points separating the, “separated brethren,” is their desire for certainty about the forgiveness of sins.
Pax Christi nobiscum.
John Hiner