All 3 Uses of

earnest

in

Othello, the Moor of Venice

This to hear Would Desdemona seriously incline: But still the house affairs would draw her thence; Which ever as she could with haste despatch, She'd come again, and with a greedy ear Devour up my discourse; which I observing, Took once a pliant hour; and found good means To draw from her a prayer of earnest heart That I would all my pilgrimage dilate, Whereof by parcels she had something heard, But not intentively; I did consent; And often did beguile her of her tears, When I did speak of some distressful stroke That my youth suffer'd.†
Scene 1.3

earnest = sincere or serious

What will you do with't, that you have been so earnest To have me filch it?†
Scene 3.3 *

that handkerchief thou speak'st of I found by fortune and did give my husband; For often with a solemn earnestness,— More than, indeed, belong'd to such a trifle,— He begg'd of me to steal it.†
Scene 5.2

earnestness = sincerity or seriousness

Definition:

characterized by sincere belief

or:

intensely or excessively serious or determined