Earnest (adjective)

1. Showing or characterized by a sincere and intense conviction.
2. Not joking or trifling.
3. Serious or sober in intention or nature.
4. Done or performed with full dedication or sincerity.

Origin:

Middle english: from old french erne(s)t "serious", from latin earnestus, from e(x) "out of" + arnus "lamb" (a pledge being symbolized by a lamb in ancient times).

Examples:

1. She made an earnest request to the committee.
2. The new teacher was an earnest young man, determined to make a difference.
3. The artist was known for his earnest approach to his work, producing only what he felt was true to himself.
4. The young couple had an earnest conversation, discussing their future together.
5. The musician was renowned for his earnest performances, delivering each piece with intensity and passion.