Can someone please comment how to nurture my positive thoughts?

I have been trying to manifest a certain kind of life for myself, but I don't know if I am doing a good enough job.

In reality, it seems far-fetched and too good to be true, but there's a certain deep part of me that believes it WILL happen exactly how I want it to. Like whenever I have doubts, a part of my heart or brain tells me that it's possible, and it will happen, that it HAS to.

I want to nurture this positive feeling so that it actually comes to fruition, but how? If anyone can guide me, please, I'd really appreciate it.