When we first hit ____ the idea, everyone told us it would never work.

• Complete sentence: When we first hit on the idea, everyone told us it would never work.
- Bangla meaning: যখন আমরা প্রথম এই ধারণাটি খুঁজে পেয়েছিলাম, সবাই আমাদের বলেছিল যে এটা কখনো কাজ করবে না।

• Hit (on/upon) something [phrasal verb]
- English Meaning: To think of an idea when you didn't expect or intend to, especially one that solves a problem.
- Bangla Meaning: অপ্রত্যাশিতভাবে বা দৈবক্রমে আবিষ্কার করা; (কোনোকিছু) হঠাৎ মনে উদয় হওয়া।

• More example:
1. Rajib hit upon an excellent idea.
2. That’s when I hit on the idea of giving the work to Caroline.

• Hit with (hit sb with sth)
- English Meaning: To shock someone by telling them something which they did not expect, or by demanding a lot of money from them.
- Example: He spent twenty minutes checking over the car and then he hit me with a bill for £120!

Source:
1. Accessible Dictionary by Bangla Academy.
2. Cambridge Dictionary.