﴿فَذَلِكُنَّ الَّذِي لُمْتُنَّنِي فِيهِ﴾
That is the one concerning whom you blamed me. (Yūsuf 12:32)
The clause naturally presupposes a ground for the blame. Within the story, the implied relation is understood as fī ḥubbihi, “in my love for him.” Reason can establish that blame has a reason, but not identify that reason by itself.
The earlier mention of attraction and pursuit supplies the missing specificity. This is a combined case of reason, context and customary understanding.
The earlier statements about love and attempted persuasion support this reading; the relevant clue need not be immediately adjacent.