「Person, rod head sliding with emphasis on rod, palming control, changing state once and once again with orifice」certainly is AT WILL, AT RANDOM, and being the safest form of sex, is undeniably TRUSTED, BELIEVABLE as ubiquitous, and preserves FIDELITY if promise-bound: personal intercourse.
Apparently equates 'whom do you love?' with 'whom do you trust'? and a「person's words, speech」cannot fit the given external source meanings in many cases: in a perfect world, a「person」with「word」should always be BELIEVABLE…but is that so? (see 諶) the simple concept of「person's words」does not automatically equate to TRUST, FAITH, BELIEF, and may actually inspire the opposite in many cases, since if a targeted individual is too trusting and gullible, then it is likely another malicious person will attempt to take advantage.
「Person's verbal intercourse」in the old days being a LETTER, WRITTEN CORRESPONDENCE.
Nevertheless,「person and sexual intercourse」had better always be a relationship based upon TRUST, and may be the case representing the most possible trust of another person, especially a few thousand years ago when society and life was far simpler than it is today, when「person and sexual intercourse」also meant AT RANDOM and AT WILL with the nearest available warm orifice…or, a cold orifice for necrophiliacs. Consider the contrary case: why would anyone engage in sexual intercourse with someone who was distrusted, or someone believed to be carrying disease? you can bet that all involved must have SINCERE FAITH and TRUST, BELIEVING in particular that no physical harm will come of it. TRUST being warranted is not always the case of course—ask anyone who has contracted the clap, genital herpes, warts, the pox, crabs, or some other problem at one time or another due to sexual intercourse, a group that health organizations report constitutes well more than half of the present-day population on Earth, and a much larger percentage in the good old days of a few thousand years ago when there were no antibiotics.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: letter; mail; to trust; to believe; to profess faith in; truthful; confidence; trust; at will; at random
Japanese EDRDG: faith, truth, fidelity, trust
Unihan extended: trust, believe; letter

Used within names (nanori)
し　･　しが　･　しな　･　しの　･　しぶ　･　とき　･　のび　･　のぶ　･　まこと