To be yourself in English, you can say "to be true to oneself" or "to be genuine." This means to act in a way that is authentic and aligns with your own beliefs, values, and personality, rather than trying to be someone else or pretending to be something you're not. This phrase comes from the idea that being true to oneself involves staying true to your own identity and being honest with yourself and others.

Here are some example sentences:

"I think it's important to be true to yourself and not try to be someone else." (重要的是做真实的自己，不要试图成为别人。)

"It's never too late to be genuine and start living your life authentically." (永远不要晚了才真实地过你的生活。)

"I admire people who are able to be themselves, even in difficult situations." (我钦佩那些即使在困难的情况下仍然能做自己的人。)