'Sure' in the Bible

Because of this it is of faith, that it may be according to grace, for the promise being sure to all the seed, not to that which is of the law only, but also to that which is of the faith of Abraham,

As to the rest, my brethren, rejoice in the Lord; the same things to write to you to me indeed is not tiresome, and for you is sure;

sure, nevertheless, hath the foundation of God stood, having this seal, 'The Lord hath known those who are His,' and 'Let him depart from unrighteousness -- every one who is naming the name of Christ.'

which we have, as an anchor of the soul, both sure and stedfast, and entering into that within the vail,