Are there any simple Quenya verbs for that? I usually say "tyar- yesta", but are there any alternatives? Unfortunately it is not easy to create a causative. Yestata- cries for haplology, and it is not known whether it should be esse or yesse. Additionally esse has two meanings, which is why it is too imprecise.
I think yesta- on itself can conceivably be used both transitively and intransitively. For an intransitive use I could imagine an inceptive form like *menu- "start, set out".
Wait, Yesta- is "to desire", isn't it? If it also means "to start", it will have two meanings. Aren't there any verbs, which are more unequivocal?
Yes, the two are homonyms, which may or may not be a problem. One can either rely on context to separate the two from each other, or generally not use the 'desire' meaning and shift it to other roots like ID or MER. Or hope that in a future publication we get an unequivocal attestation of a verb meaning "to begin"...