I'm translating a song into Japanese for my class right now, and it's driving me insane. There are these lines that I just can't put in any shorter form, I don't suppose I could get your guys' input.

No one else has what I need
When it's just us two, I get shy but you keep me cool
The way you're always watching out for me
And although I wanna believe*
Tell me I'm not just imagining

I've gotten somewhere, but I'm having a hard time with the plain versions of certain verbs. Some lines I'm just not even sure how to word.

* This is an easy sentence but I don't actually know which "although" to use:
けど信じたい
でも信じたい
仮令信じたい

I have a feeling
けど would be best, but I don't know. I'm not good at translating songs.