坚定的信心英语

firm （one's) faith

strengthen one's trust/beliefp.s.我这个是动词短语如果楼主意思是 坚定的信念 的话，就应当是firm belief若是 坚定地相信 则是 sb. firmly believes that +从句

Strong belief

有如下： strong convictions信念坚定unshakable faith 信念坚定unshakable faith 信念坚定A strongly held opinion; a conviction. 坚定的信念；信念 A will of granite. 坚定的信念 strengthen one's conviction 坚定信念 Good faith; fidelity 坚定信念；忠诚 希望帮到你！