This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
纞 combines 糸 (thread) with 戀 (love, attachment). The exact historical development is uncertain, but it likely relates to tying or connecting through affection.
The thread radical 糸 beside 戀 suggests a thread of attachment or a bond of love, but the exact meaning is unclear.
For レン, imagine a red thread of love (恋, レン) tying two people together: 恋 -> レン, and the thread 糸 reinforces the bond.