Let love be without dissimulation. Romans 12:9a
In the LDS Bible footnotes for this verse, we can see that the original Greek word translated “without dissimulation” means “sincere” and “unfeigned.” Below is a short word study on the word sincere.
“The Greek words in the New Testament for character are interesting. Many times these words are translated "sincerity.”
"The English term "sincere" comes from the Latin; in fact, it is made up of two words every first-year Latin student learns. They mean literally, "without wax.” In the ancient world pottery was a necessity of life. It was not unusual for pottery to break when it was being fired, and, of course, a broken pot was hard to sell, unless you had some wax. A skillful, but dishonest potter, could use wax as a glue and put a pot back together, paint it, and sell it as new. That was fine, of course, until a person poured hot soup into the pot. So some potters of integrity began to advertise their wares as "sine cere," without wax, and they would encourage their buyers to hold the pot up to the sun or subject it to heat to try to detect any wax.
The original Greek word translated "sincere" is sometimes rendered "without hypocrisy." "Let love be without hypocrisy." This is another very picturesque term. It means literally, "to speak from down under," and its derivation is from the ancient theater. Actors didn’t normally dress their parts–they just carried masks which indicated whether they were playing a comic, dramatic, or melodramatic role. Every once in a while they would put the mask up to their face to remind the audience of the character being portrayed. When the mask was up, of course, they had to "speak from down under it." Hypocrisy, then, is speaking from under a mask.
Paul here demands of the believer a love that wears no masks, that sports no wax, a love that holds up under both heat and light."