An act of love prompted by guilt isn’t really love at all. It’s selfishness, to ease the guilt we’re experiencing.
But real love isn’t selfish. It’s selfless, putting the well-being of the other person ahead of our own feelings or well-being. This cannot be accomplished through guilt, because of the way guilt-based motives are inherently self-focused; meaning, the focus of this “act of love” inevitably becomes us, ourselves, instead of the the person we’re supposed to be helping/loving.
Love also can’t be accomplished through fear. There is no fear in love, but perfect love casts out fear, because fear has to do with punishment. The one who fears is not made perfect in love.