-What is faith?
"Faith is the assurance of things hoped for, the conviction of things not seen." -Hebrews 11-1
-How can I grow in this faith?
Faith tends to get very difficult with uncertanties but more importantly, when we don't want to give ourselves up freely. We still want to have control in our lives so we don't allow God to fulfill His works because we don't have faith in Him.
-How can we have faith in anything if we can't put our trust in IT, which is through allowing ourselves to be vulnerable?
To not have faith means to reject a possibility of God because we're afraid of opening ourselves up to the unknown. But we need to understand that God is infinite Love, and if we close ourselves to the possibility to receive that love, it will make it so much harder to come back. Understand too that faith in something does not mean you have a direct answer. That is the whole point of faith. That through your trust, you hope the outcome to be the best. The more faithful you are to God, the more you can trust in His Will, whatever that may be. And through this strong faith, you're able to receive Him and His grace easier. Pray that you're able to have faith in God like the saints did. For suffering in this world, they had faith in God that they may be saved and have eternal life in paradise and see God face to face.
There are times when I feel and tell myself that only if I heard God's voice, felt His presence or saw Him, it would make me truly believe and satisfy my life here on earth. It's easy to think that if any of these were to happen, our faith would be so strengthened and rooted, that we would never turn from God or sin. But think of a child who so desparately wants a toy, and believes that through receiving it, they will be fully satisfied. Little do they know, as we do, that fulfillment in the toy fades quicker than expected. How then can I want these signs from God, when I have little to no faith? Because if I truly did have faith, I would know that if I were to receive one of these signs or not, I would fully be satisfied in Him, unlike the child and their toy. That is why God tests our faith, so that when it is time to fully receive Him, we will be totally filled with satisfaction, so that nothing on earth, nor in Heaven, will want us to turn from Him. Have faith in believing He is always with you, even though you may not "feel" Him. Just as a shepard doesn't leave one of his sheep behind, so He will do with you, and will always be by your side.