想問一下當產生共鳴的時候，然後你會突然有一股勇氣做出你平時不敢做的事。（例如當看日全蝕的時候，你會突然敢向喜歡的人表白。）這種感受可以用一個英文的詞語形容嗎？感謝萬分！我也做過很多搜尋資料，有resonance這個字，但又好像反映不出有勇氣這個意思。?

雖然你查到的英文字跟你感覺"共鳴"是唯一的對等名詞，但明顯你感覺反映不出你的那種"真實感覺"，因此我們要擺脫以字查字的方法，而要用文化感受的方法來選詞，即是要問英語人在同樣/類似的情景/處境時他們會用甚麼"形容詞"來描寫自己的這種"外來產生力量"的感受。

我也不能說我是100%認識英語人的說法，以下只是提供一個可能的形容方式：

boost up (courage) 反譯中文=提昇勇氣
summon up (courage) 反譯中文=鼓足勇氣

至於你的例子的情況形容的是"超自然"的感動或者"被感召"的話，則可能是(被動式的說法)：
being inspired to (declare my love for "you")
being moved to (say I love "you")
being possessed to (profess my love for "you")

Inspire with hope, with enthusiasm, with confidence
to show love towards your lover for the sake of love supposed to make her falls in love with you from whom solar eclipse is something given as a symbol of love.
Inspire with hope:-eg:-I hope this Solar Eclipse Phenomenon will inspire my GF to be inspired by the Solar Eclipse Phenomenon.
Inspire with enthusiasm:-eg:-I need the Solar Eclipse Phenonmenon who can inspire my GF with enthusiasm
=Solar Eclipse Phenomenon inspired my GF to take up my love with enthusiasm.
Inspire with confidence:-eg:-Make her feel confident because she trusts my love
=My love inspires her confidence.
Love is inspired by a chance meeting with the Solar Eclipse Phenonmenon
=I need Solar Eclipse Phenonmenon who can inspire my GF
The Solar Eclipse Phenonmenon encourage me by making me feel confident and eager to do something on my GF.

whim
From Longman Dictionary of Contemporary English
a sudden feeling that you would like to do or have something, especially when there is no important or good reason

We all stay on the same page.

當看日全蝕的時候，你會突然敢向喜歡的人表白==While you watch the solar eclipse then suddenly felt to express your loving one. Yip