If we ask for something according to God’s will, He will hear us - 1 John 5:15
And this is the confidence that we have in him, that, if we ask any thing according to his will, he heareth us: And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him.
John wrote about the confidence we have in Christ. We can ask anything according to His will and He will hear us. The way that we know that we are heard, we receive what we asked for.