Questions & Answers about Ik vind dit horloge erg mooi.
Why do we use dit instead of deze for "this watch"?
Because horloge is a het-word (het horloge). When saying "this", you must use dit for het-words and deze for de-words.
Why use vind here instead of a word for "think" or "like"?
The verb vinden (to find) is the standard way to express a personal opinion in Dutch. When you want to say "I think this watch is beautiful" or "I like this watch", the most natural phrasing is Ik vind dit horloge mooi.
Could I use heel instead of erg?
Absolutely. Heel mooi and erg mooi mean the exact same thing: "very beautiful". You can use them interchangeably before an adjective.
I thought erg meant "terrible". Why is it used with mooi?
Erg does mean "terrible" or "bad" when used on its own as an adjective. However, when placed right before another adjective, it simply becomes an adverb meaning "very".