A word for “bride” in The Etymologies of the 1930s derived from primitive ᴹ✶ndīse under the root ᴹ√NDIS (Ety/NDIS). Ordinarily the s in this word would have been lost, but it was influenced by N. †dess “young woman” < ON. ndissa from the same root (EtyAC/NDIS). Dîs “bride” in turn influenced the form of N. †dî “woman”, originally ON. nī < ᴹ√NĪ (Ety/DER, NĪ¹; EtyAC/NDIS).
Neo-Sindarin: While I think this word is perfectly serviceable, for purposes of Neo-Sindarin it may be better to use the longer and more distinctive word dineth for bride.