I don't know what to say.

What does “I don't know what to say” mean?

I'm too surprised, moved or shocked to find the right words. People say it after a gift, good news or bad news.

• You are amazing./ju ɑːr əˈmeɪzɪŋ/
• Chop-chop./tʃɑːp tʃɑːp/
• You complete me./ju kəmˈpliːt mi/
• Praise be./preɪz bi/
• You are a good person./ju ɑːr ə ɡʊd ˈpɜːrsən/
• Nice try./naɪs traɪ/
• You guys rock./ju ɡaɪz rɑːk/
• My conscience is clear./maɪ ˈkɑːnʃəns ɪz klɪr/