Sincerity

Sin*cer"i*ty (?), n. [L. sinceritas: cf. F. sincérité.] The quality or state of being sincere; honesty of mind or intention; freedom from simulation, hypocrisy, disguise, or false pretense; sincereness.

I protest, in the sincerity of love.
Shak.

Sincerity is a duty no less plain than important.
Knox.