首先要搞清楚你说的“相信”到底是什么意思
汉语中相信有两个意思:
1、相信某件事情是真的(或者假),相信某人的话。翻译成英语为believe
2、信任某人,信任某事。翻译成英语为believe in 或者trust
根据句子,可以明显判断楼主想要表达的是“信任”,所以可以用believe in 或者trust
自信,翻译为confident或者self-confident
翻译:
I believe in(trust) myself, and I am very confident
I believe in myself, I am very confident!
I believe in myself, I am very confident!
I believe in yourself, I am very confident!