Buy a Serendipity Nice Coincidence calligraphy wall scroll here!
素敵な偶然 is a common way to express serendipity in Japanese.
The first two characters mean nice, lovely, dreamy, beautiful, great, fantastic, superb, or cool.
In the middle is a Japanese Hiragana character connecting these words/ideas.
The last two Kanji mean incidentally, by chance, randomly, unexpectedly, suddenly, accident, fortuity, or by coincidence.