no one can know, in this life, whether one is joined to God's love in the first place.
Well, we Reformers stand with Paul when he declares "for I know whom I have believed" (2 Timothy 1:12.)
Since you seem interested, please read the following excellent link by Loraine Boettner...
"...Those who have fled to Jesus for refuge have a firm foundation upon which to build. Though floods of error deluge the land, though Satan raise all the powers of earth and all the iniquities of their own hearts against them, they shall never fail; but, persevering to the end, they shall inherit those mansions which have been prepared for them from the foundation of the world. The saints in heaven are happier but no more secure than are true believers here in this world. Since faith and repentance are gifts of God, the bestowing of these gifts is a revelation of God's purpose to save those to whom they are given. It is an evidence that God has predestinated the recipients of these gifts to be conformed to the image of His Son, i.e., to be like Him in character, destiny, and glory, and that He will infallibly carry out His purpose. No one can pluck them out of His hands. Those who once become true Christians have within themselves the principle of eternal life, which principle is the Holy Spirit; and since the Holy Spirit dwells within them they are already potentially holy. True, they are still exercised by many trials, and they do not yet see what they shall be, but they should know that that which is begun in them shall be completed to the end, and that the very presence of strife within them is the sign of life and the promise of victory..."
Knowing whom you have believed is not the same as knowing that you are elect. Even those who will eventually fall away know whom they have believed. Is that the best you can do??
-A8
While in seminary Greg would have told him the same thing you quote from Boettner, "Since faith and repentance are gifts of God, the bestowing of these gifts is a revelation of God's purpose to save those to whom they are given. It is an evidence that God has predestinated the recipients of these gifts to be conformed to the image of His Son, i.e., to be like Him in character, destiny, and glory, and that He will infallibly carry out His purpose."
The imaginary world in which everyone who shows "faith and repentance" remains a believer until death is just that, imaginary. Reformed folk who claim otherwise are just deceiving themselves. It is if you are completely unaware (or in complete denial) about the *fact* of people who show "faith and repentance", and then go on to become God-hating atheists.
-A8