Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!

Qenya 

qáqínen

adverb. *by all means

The correlative ᴹQ. qáqínen appeared in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 (PE23/111), a combination of ᴹQ. qa(qe)- “all” and the instrumental suffix ᴹQ. -nen.

Neo-Quenya: For purposes of Neo-Quenya I would update this to ᴺQ. illinen “by all means” using il- “all”.